Applied Evidence

Approximately 60 million people in the United States run for exercise at least once a calendar year, with approximately 11 million of them running > 100 days a year.^1,2 Running is an affordable, convenient, and efficient form of exercise, whose benefits include a decrease in the risk of all-cause early mortality, cancer, and diabetes; an improved lipid profile; and better mental health.³

However, running is also the cause of a significant percentage of exercise-associated injuries: More than 60% of runners report overuse injury annually.⁴ Given the high incidence of running-related injury, an important component of primary care is accurately diagnosing and managing such injuries and counseling patients about how to prevent them.

This article reviews risk factors for running-related injury and summarizes evidence-based recommendations for prevention.

CASE

During a health maintenance examination, Clara K, a 47-year-old woman who is obese (body mass index [BMI], 34) and has bilateral knee osteoarthritis (OA), inquires about establishing a weight-loss strategy. Ms. K is interested in starting an exercise regimen involving running but is worried about provoking a flare of OA pain.

Risk factors for running injuries

Several risk factors—some modifiable, others nonmodifiable—are associated with running-related injury (TABLE 1^4-16). In addition, research suggests that other variables once thought to be risk factors, such as running surface and the Q-angle (described later), are not associated with running-related injury.

Modifiable risk factors

Changes in a training regimen or type of training. Many runners escalate training regimens as their fitness improves. Increasing mileage and changing the type of training (such as introducing hills or interval training) are independent risk factors for sustaining injury.⁵

Running is an affordable, convenient, and efficient form of exercise; however, more than 60% of runners report overuse injury annually.

The traditional recommendation has been for a runner to slowly increase or modify training with a 10% weekly increase in mileage or intensity.¹⁷ However, a randomized controlled trial failed to show a lower incidence of injury among amateur runners who adopted a graded exercise program.¹⁸ Regardless: It is still prudent to recommend a gradual increase in activity, such as taking ≥ 1 day off between running workouts or starting with a walking or jogging program, especially when there is a history of injury.¹⁹

Continue to: Excessive mileage

Excessive mileage. Many runners aspire to complete high-mileage runs. There is low-quality evidence demonstrating that high-mileage running, especially > 40 miles per week, is associated with increased risk of running-related injury.⁵ Injuries that occur with higher mileage are more often those of the hip and hamstring.⁵ A study noted that running ≤ 25 miles a week was protective against calf injury.⁶

Overall, there is little evidence to show that high-mileage running is associated with increased risk of running-related injury. However, this is still a risk factor that you should address with patients who have a running program—especially novices and those who ramp up mileage quickly.

Type of surface. Access to running surfaces—concrete, pavement, trails, treadmills, and athletic tracks—varies by time of day and season. Softer surfaces include treadmill, tracks, and trails; harder surfaces include asphalt and concrete.

There are limited data linking running surface with risk of injury.⁷ A study did not find an association between peak impact force based on running surface⁸; the authors hypothesized that runners compensate for a harder surface by making kinematic adjustments to minimize impact. With no strong evidence to link running-related injury to a particular running surface, patients should not be restricted to a softer running surface unless they notice a difference in comfort, because it is likely that they can compensate for a harder surface by adapting their gait.

Patients can therefore be counseled to run locally on sidewalks and neighborhood streets—if safe to do so—instead of obtaining a gym membership or driving to run on a trail. Such reassurance can increase a patient’s access to running and reduce barriers to exercise.

Continue to: BMI

BMI. Elevated BMI increases joint contact forces, which might increase risk of pain and injury.²⁰ Results of studies investigating the link between BMI and running injury are mixed; some report that, in regard to bone stress injury, overweight BMI (> 25) is a risk factor for male runners and underweight BMI (< 18.5) is a risk factor for female runners.^4,6 An observational study concluded that, among half-marathon and marathon runners, there was no significant increase in race-related injury, based on BMI.⁹ However, another study showed a higher rate of running-related injury in novice runners who had a higher BMI.¹⁰ A prospective cohort study found that runners with a higher BMI reported increased knee stiffness, which can place a runner at higher risk of overuse injury.⁴

Although these results conflict, there is consistency in the finding that obese novice runners are likely at increased risk of running-related injury; it is reasonable, therefore, for you to discuss strategies to reduce the risk of other modifiable factors, especially among obese novice runners. Patients with a higher BMI should not be discouraged from running, because exercise in combination with healthy eating habits is essential to decrease the myriad adverse health outcomes associated with obesity.

Female runners with a lower BMI, especially in the presence of other components of the female athlete triad (inadequate nutrition, amenorrhea, and low bone density), should be counseled about their increased risk of bone stress injury.²¹ Notably, a study of female US Navy recruits randomized to receive a trial of dietary supplementation of vitamin D plus calcium, or placebo, showed a 21% lower incidence of bone stress injury in the active-treatment group.²² To mitigate risk of injury associated with low BMI and the female athlete triad, therefore, a multidisciplinary approach of nutrition intervention, dietary optimization of vitamin D and calcium, and, possibly, activity modification should be implemented when appropriate.

Running gait. A study using 2-dimensional gait analysis to visualize biomechanical running patterns in injured and noninjured runners found that, in regard to mechanical variables, running-related injury was most strongly associated with contralateral pelvic drop.²³ Gait retraining can be employed to help decrease contralateral pelvic drop.²⁴ In addition, pelvic drop is often a result of weak gluteal muscles, and can be improved by doing strengthening exercises at home or with physical therapy.

Longer stride is also associated with running-related injury.²⁵ A study showed improvement in patellofemoral pain by having runners increase stride rate by 10%, which reduces stride length to a significant degree.^25,26 These improvements were maintained at 1-month and 3-month follow-up, and required only 1 gait retraining session.

Continue to: Get analysis is not feasible...

Gait analysis is not feasible in most primary care clinics. Instead, patients who run and (1) in whom pain persists despite more traditional treatments and (2) who have had recurring injury should be referred to a gait lab for analysis, usually by a physical therapist.

Nonmodifiable risk factors

Arch height. A high arch (pes cavus) is associated with increased risk of running-related injury, including bone stress injury, Achilles tendinopathy, plantar fasciitis, and patellofemoral pain syndrome.⁵ The mechanism of injury is thought to be increased forefoot loading forces.¹

A review article showed that patients with pes cavus have reduced pain when using an orthosis, although there is no associated decrease in the risk of injury.⁵ To the contrary, a prospective study concluded that arch height was unrelated to increased risk of running-related injury.⁷

A study showed improvement in patellofemoral pain by having runners increase stride rate by 10%, which reduces stride length to a significant degree.

Evidence regarding flat feet (pes planus) and risk of injury is also mixed. Some studies show that pes planus is not associated with increased risk of injury in athletes.¹² A cross-sectional study in older patients showed those with pes planus morphology had a higher rate of knee pain and wearing away of medial compartment cartilage.¹³ Because this study comprised only older adults, it is not generalizable to runners—nor can conclusions be drawn about causation, given the cross-sectional nature of the study.

Although a foot orthosis can correct mechanical differences caused by pes planus morphology, there is not enough evidence to conclude that correction results in a lower rate of injury. In sum, data are mixed with regard to arch height as a risk factor for running-related injury.

Continue to: Patients with...

Patients with pes planus or pes cavus should not be discouraged from running, however. If they experience pain with running, they might benefit from a trial of arch support inserts; or consider referral to an orthotist for evaluation for a custom orthosis.

Sex. Based on a prospective cohort study, female runners have a slightly higher rate of running injury than male counterparts.⁴ Similarly, a study showed that female military members generally had a higher incidence of stress fractures than male military members—specifically, femoral shaft and neck stress fractures.¹⁴ Runners who fall in the spectrum of the female athlete triad, as described earlier, are particularly vulnerable to bone stress injury. It is reasonable, therefore, to review risk factors for injury with female runners (as it is with all runners), especially those who have sustained a prior running-related injury.

Increased Q-angle (an obsolete risk factor). The Q-angle is approximated by drawing a line from the anterior superior iliac spine to the patella and a second line from the patella to the tibial tubercle. In males, a normal Q-angle is 14°; in females, 17° (SD = 4.5°). The Q-angle can be obtained by goniometric or radiographic measurement.

An increased Q-angle had been considered an intrinsic risk factor for running injury but has not been shown to be associated with increased risk of running-related injury or patellofemoral pain syndrome.^27,28 Because the Q-angle is not a clinically relevant tool in assessing risk of injury, do not routinely measure it or include it in risk-factor counseling.

OA. Based on a systematic review of observational studies, data are inconclusive with regard to whether running contributes to, or is protective against, knee OA.¹⁵ In a large cohort study, running (1) was protective against development of hip OA and (2) decreased the risk of requiring hip replacement.²⁹ This finding was supported by animal-model research that concluded that it is inactivity that results in thinning of articular cartilage.²⁹ In addition, a systematic review of randomized controlled trials concluded that knee joint-loading exercises are not harmful to articular cartilage (this is low-quality evidence, however).¹⁶

Continue to: Given that there...

Given that there are no high-quality studies suggesting that running contributes to or exacerbates OA, patients with OA can be counseled to start or continue running as tolerated because the health benefit of running likely outweighs risk. Patients with pre-existing moderate-to-severe OA might report knee and hip pain that is already exacerbated by certain activities; if a high-impact activity, such as running, makes that pain worse, exercise counseling that you provide can be tailored to include lower-impact alternatives, such as swimming, cycling, or an elliptical workout.

CASE

In response to Ms. K’s interest in beginning an exercise regimen that includes running, you perform a complete routine pre-participation evaluation and appropriate cardiac screening. You discuss risk factors for running injury, focusing on modifiable risk factors.

High-mileage running, especially > 40 miles per week, is associated with increased risk of injury, most often of the hip and hamstring.

Ms. K is perimenopausal but reports a history of regular menstrual cycles. She eats a relatively well-balanced diet. You advise that her BMI should not restrict her from incorporating running into her fitness regimen. Also, you reassure her that she should not restrict running based on a diagnosis of OA; instead, you advise her to monitor her symptoms and reconsider her program if running makes her knee pain worse.

At this point, Ms. K is ready to run. She tells you that, based on your guidance, she feels more comfortable and safe starting a running program.

Preventing injury

After reviewing risk factors for running-­related injury with patients, encourage other evidence-based methods of reducing that risk.

Continue to: Shoes

The running shoe industry offers a variety of running shoes, from minimalist shoes to cushioned stability shoes that vary based on the amount of cushioning, level of motion control, and amount of heel-to-toe drop. With so many options, new runners might wonder which shoes can reduce their risk of injury and how they should select a pair.

Stability. A characteristic of running shoes promoted by the industry is their stability: ie, their motion control. Stability shoes are marketed to runners who overpronate and therefore limit motion to prevent overpronation. The benefit of stability shoes, or stability insoles, is unclear.³⁰ A randomized controlled trial showed that, in runners who overpronate, motion-control shoes reduced their risk of injury.³¹ However, another study assessed whether shoes that had been “prescribed” based on foot morphology and stride reduced the risk of injury (compared to neutral, cushioned shoes) and found no change in the incidence of soft-tissue injury.³² Given no strong evidence to suggest otherwise, runners can be advised to buy shoes based on comfort rather than on foot morphology or running stride.

Heel-to-toe drop. Another component of shoe variability is heel-to-toe drop (the height difference between heel and forefoot). A study suggests that moderate-to-high (8-12 mm) heel-to-toe drop is associated with a reduced risk of running injury.³³ Barefoot running shoes, which, typically, have no heel-to-toe drop, are associated with increased risk of injury—specifically, foot stress fracture (especially in runners who are even moderately overweight).^34,35

Shoe age and shoe wear can be modified to reduce injury. There is evidence that running shoes lose approximately 50% of cushioning after 300 to 500 miles of use.³⁶ Another study found that rotating running shoes—ideally, different types or brands—can lead to fewer running-related injuries.³⁷

In general, patients can be counseled to use shoes that feel comfortable, as long as they replace them regularly (TABLE 2). Runners can also consider alternating pairs of different running shoes between runs. Overweight runners should avoid minimally cushioned and low heel-to-toe drop running shoes.

Continue to: Cross-training

Cross-training exercises for runners include cycling, an elliptical workout, swimming, and weightlifting. Incorporating cross-­training can be protective against running injury because cross-training requires different movement patterns, prevents overuse, and equalizes muscle imbalances that occur with running.⁷ In addition, replacing running with a cross-training activity can decrease weekly running time and mileage, which can further reduce risk of running-related injury.⁷ Runners—especially higher-mileage runners—should be encouraged to incorporate cross-training into their workout regimen to decrease their risk of injury.

There is no reason to counsel runners to run on a softer running surface, unless they find that doing so is more comfortable.

Stretching. The authors of a Cochrane review concluded that there is no significant reduction in injury associated with hamstring or gastrocnemius stretching.³² A small randomized, controlled, crossover study concluded that participants subjectively felt their performance was better when warm-ups included stretching.³⁸ This perceived improvement in performance was similar between groups who completed dynamic or static stretching. However, no difference was noted in flexibility or objective performance between groups who stretched or did not stretch before activity.

Although there is no supporting evidence that stretching reduces the risk of injury, stretching is a low-risk intervention. Because stretching might provide subjective benefit to runners, you need not discourage patients from including this activity in their running program.

CORRESPONDENCE
Kartik Sidhar, MD, 15370 Huff Way, Brookfield, WI, 53005; [email protected]

Approximately 60 million people in the United States run for exercise at least once a calendar year, with approximately 11 million of them running > 100 days a year.^1,2 Running is an affordable, convenient, and efficient form of exercise, whose benefits include a decrease in the risk of all-cause early mortality, cancer, and diabetes; an improved lipid profile; and better mental health.³

However, running is also the cause of a significant percentage of exercise-associated injuries: More than 60% of runners report overuse injury annually.⁴ Given the high incidence of running-related injury, an important component of primary care is accurately diagnosing and managing such injuries and counseling patients about how to prevent them.

This article reviews risk factors for running-related injury and summarizes evidence-based recommendations for prevention.

CASE

During a health maintenance examination, Clara K, a 47-year-old woman who is obese (body mass index [BMI], 34) and has bilateral knee osteoarthritis (OA), inquires about establishing a weight-loss strategy. Ms. K is interested in starting an exercise regimen involving running but is worried about provoking a flare of OA pain.

Risk factors for running injuries

Several risk factors—some modifiable, others nonmodifiable—are associated with running-related injury (TABLE 1^4-16). In addition, research suggests that other variables once thought to be risk factors, such as running surface and the Q-angle (described later), are not associated with running-related injury.

Modifiable risk factors

Changes in a training regimen or type of training. Many runners escalate training regimens as their fitness improves. Increasing mileage and changing the type of training (such as introducing hills or interval training) are independent risk factors for sustaining injury.⁵

Running is an affordable, convenient, and efficient form of exercise; however, more than 60% of runners report overuse injury annually.

The traditional recommendation has been for a runner to slowly increase or modify training with a 10% weekly increase in mileage or intensity.¹⁷ However, a randomized controlled trial failed to show a lower incidence of injury among amateur runners who adopted a graded exercise program.¹⁸ Regardless: It is still prudent to recommend a gradual increase in activity, such as taking ≥ 1 day off between running workouts or starting with a walking or jogging program, especially when there is a history of injury.¹⁹

Continue to: Excessive mileage

Excessive mileage. Many runners aspire to complete high-mileage runs. There is low-quality evidence demonstrating that high-mileage running, especially > 40 miles per week, is associated with increased risk of running-related injury.⁵ Injuries that occur with higher mileage are more often those of the hip and hamstring.⁵ A study noted that running ≤ 25 miles a week was protective against calf injury.⁶

Overall, there is little evidence to show that high-mileage running is associated with increased risk of running-related injury. However, this is still a risk factor that you should address with patients who have a running program—especially novices and those who ramp up mileage quickly.

Type of surface. Access to running surfaces—concrete, pavement, trails, treadmills, and athletic tracks—varies by time of day and season. Softer surfaces include treadmill, tracks, and trails; harder surfaces include asphalt and concrete.

There are limited data linking running surface with risk of injury.⁷ A study did not find an association between peak impact force based on running surface⁸; the authors hypothesized that runners compensate for a harder surface by making kinematic adjustments to minimize impact. With no strong evidence to link running-related injury to a particular running surface, patients should not be restricted to a softer running surface unless they notice a difference in comfort, because it is likely that they can compensate for a harder surface by adapting their gait.

Patients can therefore be counseled to run locally on sidewalks and neighborhood streets—if safe to do so—instead of obtaining a gym membership or driving to run on a trail. Such reassurance can increase a patient’s access to running and reduce barriers to exercise.

Continue to: BMI

BMI. Elevated BMI increases joint contact forces, which might increase risk of pain and injury.²⁰ Results of studies investigating the link between BMI and running injury are mixed; some report that, in regard to bone stress injury, overweight BMI (> 25) is a risk factor for male runners and underweight BMI (< 18.5) is a risk factor for female runners.^4,6 An observational study concluded that, among half-marathon and marathon runners, there was no significant increase in race-related injury, based on BMI.⁹ However, another study showed a higher rate of running-related injury in novice runners who had a higher BMI.¹⁰ A prospective cohort study found that runners with a higher BMI reported increased knee stiffness, which can place a runner at higher risk of overuse injury.⁴

Although these results conflict, there is consistency in the finding that obese novice runners are likely at increased risk of running-related injury; it is reasonable, therefore, for you to discuss strategies to reduce the risk of other modifiable factors, especially among obese novice runners. Patients with a higher BMI should not be discouraged from running, because exercise in combination with healthy eating habits is essential to decrease the myriad adverse health outcomes associated with obesity.

Female runners with a lower BMI, especially in the presence of other components of the female athlete triad (inadequate nutrition, amenorrhea, and low bone density), should be counseled about their increased risk of bone stress injury.²¹ Notably, a study of female US Navy recruits randomized to receive a trial of dietary supplementation of vitamin D plus calcium, or placebo, showed a 21% lower incidence of bone stress injury in the active-treatment group.²² To mitigate risk of injury associated with low BMI and the female athlete triad, therefore, a multidisciplinary approach of nutrition intervention, dietary optimization of vitamin D and calcium, and, possibly, activity modification should be implemented when appropriate.

Running gait. A study using 2-dimensional gait analysis to visualize biomechanical running patterns in injured and noninjured runners found that, in regard to mechanical variables, running-related injury was most strongly associated with contralateral pelvic drop.²³ Gait retraining can be employed to help decrease contralateral pelvic drop.²⁴ In addition, pelvic drop is often a result of weak gluteal muscles, and can be improved by doing strengthening exercises at home or with physical therapy.

Longer stride is also associated with running-related injury.²⁵ A study showed improvement in patellofemoral pain by having runners increase stride rate by 10%, which reduces stride length to a significant degree.^25,26 These improvements were maintained at 1-month and 3-month follow-up, and required only 1 gait retraining session.

Continue to: Get analysis is not feasible...

Gait analysis is not feasible in most primary care clinics. Instead, patients who run and (1) in whom pain persists despite more traditional treatments and (2) who have had recurring injury should be referred to a gait lab for analysis, usually by a physical therapist.

Nonmodifiable risk factors

Arch height. A high arch (pes cavus) is associated with increased risk of running-related injury, including bone stress injury, Achilles tendinopathy, plantar fasciitis, and patellofemoral pain syndrome.⁵ The mechanism of injury is thought to be increased forefoot loading forces.¹

A review article showed that patients with pes cavus have reduced pain when using an orthosis, although there is no associated decrease in the risk of injury.⁵ To the contrary, a prospective study concluded that arch height was unrelated to increased risk of running-related injury.⁷

A study showed improvement in patellofemoral pain by having runners increase stride rate by 10%, which reduces stride length to a significant degree.

Evidence regarding flat feet (pes planus) and risk of injury is also mixed. Some studies show that pes planus is not associated with increased risk of injury in athletes.¹² A cross-sectional study in older patients showed those with pes planus morphology had a higher rate of knee pain and wearing away of medial compartment cartilage.¹³ Because this study comprised only older adults, it is not generalizable to runners—nor can conclusions be drawn about causation, given the cross-sectional nature of the study.

Although a foot orthosis can correct mechanical differences caused by pes planus morphology, there is not enough evidence to conclude that correction results in a lower rate of injury. In sum, data are mixed with regard to arch height as a risk factor for running-related injury.

Continue to: Patients with...

Patients with pes planus or pes cavus should not be discouraged from running, however. If they experience pain with running, they might benefit from a trial of arch support inserts; or consider referral to an orthotist for evaluation for a custom orthosis.

Sex. Based on a prospective cohort study, female runners have a slightly higher rate of running injury than male counterparts.⁴ Similarly, a study showed that female military members generally had a higher incidence of stress fractures than male military members—specifically, femoral shaft and neck stress fractures.¹⁴ Runners who fall in the spectrum of the female athlete triad, as described earlier, are particularly vulnerable to bone stress injury. It is reasonable, therefore, to review risk factors for injury with female runners (as it is with all runners), especially those who have sustained a prior running-related injury.

Increased Q-angle (an obsolete risk factor). The Q-angle is approximated by drawing a line from the anterior superior iliac spine to the patella and a second line from the patella to the tibial tubercle. In males, a normal Q-angle is 14°; in females, 17° (SD = 4.5°). The Q-angle can be obtained by goniometric or radiographic measurement.

An increased Q-angle had been considered an intrinsic risk factor for running injury but has not been shown to be associated with increased risk of running-related injury or patellofemoral pain syndrome.^27,28 Because the Q-angle is not a clinically relevant tool in assessing risk of injury, do not routinely measure it or include it in risk-factor counseling.

OA. Based on a systematic review of observational studies, data are inconclusive with regard to whether running contributes to, or is protective against, knee OA.¹⁵ In a large cohort study, running (1) was protective against development of hip OA and (2) decreased the risk of requiring hip replacement.²⁹ This finding was supported by animal-model research that concluded that it is inactivity that results in thinning of articular cartilage.²⁹ In addition, a systematic review of randomized controlled trials concluded that knee joint-loading exercises are not harmful to articular cartilage (this is low-quality evidence, however).¹⁶

Continue to: Given that there...

Given that there are no high-quality studies suggesting that running contributes to or exacerbates OA, patients with OA can be counseled to start or continue running as tolerated because the health benefit of running likely outweighs risk. Patients with pre-existing moderate-to-severe OA might report knee and hip pain that is already exacerbated by certain activities; if a high-impact activity, such as running, makes that pain worse, exercise counseling that you provide can be tailored to include lower-impact alternatives, such as swimming, cycling, or an elliptical workout.

CASE

In response to Ms. K’s interest in beginning an exercise regimen that includes running, you perform a complete routine pre-participation evaluation and appropriate cardiac screening. You discuss risk factors for running injury, focusing on modifiable risk factors.

High-mileage running, especially > 40 miles per week, is associated with increased risk of injury, most often of the hip and hamstring.

Ms. K is perimenopausal but reports a history of regular menstrual cycles. She eats a relatively well-balanced diet. You advise that her BMI should not restrict her from incorporating running into her fitness regimen. Also, you reassure her that she should not restrict running based on a diagnosis of OA; instead, you advise her to monitor her symptoms and reconsider her program if running makes her knee pain worse.

At this point, Ms. K is ready to run. She tells you that, based on your guidance, she feels more comfortable and safe starting a running program.

Preventing injury

After reviewing risk factors for running-­related injury with patients, encourage other evidence-based methods of reducing that risk.

Continue to: Shoes

The running shoe industry offers a variety of running shoes, from minimalist shoes to cushioned stability shoes that vary based on the amount of cushioning, level of motion control, and amount of heel-to-toe drop. With so many options, new runners might wonder which shoes can reduce their risk of injury and how they should select a pair.

Stability. A characteristic of running shoes promoted by the industry is their stability: ie, their motion control. Stability shoes are marketed to runners who overpronate and therefore limit motion to prevent overpronation. The benefit of stability shoes, or stability insoles, is unclear.³⁰ A randomized controlled trial showed that, in runners who overpronate, motion-control shoes reduced their risk of injury.³¹ However, another study assessed whether shoes that had been “prescribed” based on foot morphology and stride reduced the risk of injury (compared to neutral, cushioned shoes) and found no change in the incidence of soft-tissue injury.³² Given no strong evidence to suggest otherwise, runners can be advised to buy shoes based on comfort rather than on foot morphology or running stride.

Heel-to-toe drop. Another component of shoe variability is heel-to-toe drop (the height difference between heel and forefoot). A study suggests that moderate-to-high (8-12 mm) heel-to-toe drop is associated with a reduced risk of running injury.³³ Barefoot running shoes, which, typically, have no heel-to-toe drop, are associated with increased risk of injury—specifically, foot stress fracture (especially in runners who are even moderately overweight).^34,35

Shoe age and shoe wear can be modified to reduce injury. There is evidence that running shoes lose approximately 50% of cushioning after 300 to 500 miles of use.³⁶ Another study found that rotating running shoes—ideally, different types or brands—can lead to fewer running-related injuries.³⁷

In general, patients can be counseled to use shoes that feel comfortable, as long as they replace them regularly (TABLE 2). Runners can also consider alternating pairs of different running shoes between runs. Overweight runners should avoid minimally cushioned and low heel-to-toe drop running shoes.

Continue to: Cross-training

Cross-training exercises for runners include cycling, an elliptical workout, swimming, and weightlifting. Incorporating cross-­training can be protective against running injury because cross-training requires different movement patterns, prevents overuse, and equalizes muscle imbalances that occur with running.⁷ In addition, replacing running with a cross-training activity can decrease weekly running time and mileage, which can further reduce risk of running-related injury.⁷ Runners—especially higher-mileage runners—should be encouraged to incorporate cross-training into their workout regimen to decrease their risk of injury.

There is no reason to counsel runners to run on a softer running surface, unless they find that doing so is more comfortable.

Stretching. The authors of a Cochrane review concluded that there is no significant reduction in injury associated with hamstring or gastrocnemius stretching.³² A small randomized, controlled, crossover study concluded that participants subjectively felt their performance was better when warm-ups included stretching.³⁸ This perceived improvement in performance was similar between groups who completed dynamic or static stretching. However, no difference was noted in flexibility or objective performance between groups who stretched or did not stretch before activity.

Although there is no supporting evidence that stretching reduces the risk of injury, stretching is a low-risk intervention. Because stretching might provide subjective benefit to runners, you need not discourage patients from including this activity in their running program.

CORRESPONDENCE
Kartik Sidhar, MD, 15370 Huff Way, Brookfield, WI, 53005; [email protected]

Approximately 60 million people in the United States run for exercise at least once a calendar year, with approximately 11 million of them running > 100 days a year.^1,2 Running is an affordable, convenient, and efficient form of exercise, whose benefits include a decrease in the risk of all-cause early mortality, cancer, and diabetes; an improved lipid profile; and better mental health.³

However, running is also the cause of a significant percentage of exercise-associated injuries: More than 60% of runners report overuse injury annually.⁴ Given the high incidence of running-related injury, an important component of primary care is accurately diagnosing and managing such injuries and counseling patients about how to prevent them.

This article reviews risk factors for running-related injury and summarizes evidence-based recommendations for prevention.

CASE

During a health maintenance examination, Clara K, a 47-year-old woman who is obese (body mass index [BMI], 34) and has bilateral knee osteoarthritis (OA), inquires about establishing a weight-loss strategy. Ms. K is interested in starting an exercise regimen involving running but is worried about provoking a flare of OA pain.

Risk factors for running injuries

Several risk factors—some modifiable, others nonmodifiable—are associated with running-related injury (TABLE 1^4-16). In addition, research suggests that other variables once thought to be risk factors, such as running surface and the Q-angle (described later), are not associated with running-related injury.

Modifiable risk factors

Changes in a training regimen or type of training. Many runners escalate training regimens as their fitness improves. Increasing mileage and changing the type of training (such as introducing hills or interval training) are independent risk factors for sustaining injury.⁵

Running is an affordable, convenient, and efficient form of exercise; however, more than 60% of runners report overuse injury annually.

The traditional recommendation has been for a runner to slowly increase or modify training with a 10% weekly increase in mileage or intensity.¹⁷ However, a randomized controlled trial failed to show a lower incidence of injury among amateur runners who adopted a graded exercise program.¹⁸ Regardless: It is still prudent to recommend a gradual increase in activity, such as taking ≥ 1 day off between running workouts or starting with a walking or jogging program, especially when there is a history of injury.¹⁹

Continue to: Excessive mileage

Excessive mileage. Many runners aspire to complete high-mileage runs. There is low-quality evidence demonstrating that high-mileage running, especially > 40 miles per week, is associated with increased risk of running-related injury.⁵ Injuries that occur with higher mileage are more often those of the hip and hamstring.⁵ A study noted that running ≤ 25 miles a week was protective against calf injury.⁶

Overall, there is little evidence to show that high-mileage running is associated with increased risk of running-related injury. However, this is still a risk factor that you should address with patients who have a running program—especially novices and those who ramp up mileage quickly.

Type of surface. Access to running surfaces—concrete, pavement, trails, treadmills, and athletic tracks—varies by time of day and season. Softer surfaces include treadmill, tracks, and trails; harder surfaces include asphalt and concrete.

There are limited data linking running surface with risk of injury.⁷ A study did not find an association between peak impact force based on running surface⁸; the authors hypothesized that runners compensate for a harder surface by making kinematic adjustments to minimize impact. With no strong evidence to link running-related injury to a particular running surface, patients should not be restricted to a softer running surface unless they notice a difference in comfort, because it is likely that they can compensate for a harder surface by adapting their gait.

Patients can therefore be counseled to run locally on sidewalks and neighborhood streets—if safe to do so—instead of obtaining a gym membership or driving to run on a trail. Such reassurance can increase a patient’s access to running and reduce barriers to exercise.

Continue to: BMI

BMI. Elevated BMI increases joint contact forces, which might increase risk of pain and injury.²⁰ Results of studies investigating the link between BMI and running injury are mixed; some report that, in regard to bone stress injury, overweight BMI (> 25) is a risk factor for male runners and underweight BMI (< 18.5) is a risk factor for female runners.^4,6 An observational study concluded that, among half-marathon and marathon runners, there was no significant increase in race-related injury, based on BMI.⁹ However, another study showed a higher rate of running-related injury in novice runners who had a higher BMI.¹⁰ A prospective cohort study found that runners with a higher BMI reported increased knee stiffness, which can place a runner at higher risk of overuse injury.⁴

Although these results conflict, there is consistency in the finding that obese novice runners are likely at increased risk of running-related injury; it is reasonable, therefore, for you to discuss strategies to reduce the risk of other modifiable factors, especially among obese novice runners. Patients with a higher BMI should not be discouraged from running, because exercise in combination with healthy eating habits is essential to decrease the myriad adverse health outcomes associated with obesity.

Female runners with a lower BMI, especially in the presence of other components of the female athlete triad (inadequate nutrition, amenorrhea, and low bone density), should be counseled about their increased risk of bone stress injury.²¹ Notably, a study of female US Navy recruits randomized to receive a trial of dietary supplementation of vitamin D plus calcium, or placebo, showed a 21% lower incidence of bone stress injury in the active-treatment group.²² To mitigate risk of injury associated with low BMI and the female athlete triad, therefore, a multidisciplinary approach of nutrition intervention, dietary optimization of vitamin D and calcium, and, possibly, activity modification should be implemented when appropriate.

Running gait. A study using 2-dimensional gait analysis to visualize biomechanical running patterns in injured and noninjured runners found that, in regard to mechanical variables, running-related injury was most strongly associated with contralateral pelvic drop.²³ Gait retraining can be employed to help decrease contralateral pelvic drop.²⁴ In addition, pelvic drop is often a result of weak gluteal muscles, and can be improved by doing strengthening exercises at home or with physical therapy.

Longer stride is also associated with running-related injury.²⁵ A study showed improvement in patellofemoral pain by having runners increase stride rate by 10%, which reduces stride length to a significant degree.^25,26 These improvements were maintained at 1-month and 3-month follow-up, and required only 1 gait retraining session.

Continue to: Get analysis is not feasible...

Gait analysis is not feasible in most primary care clinics. Instead, patients who run and (1) in whom pain persists despite more traditional treatments and (2) who have had recurring injury should be referred to a gait lab for analysis, usually by a physical therapist.

Nonmodifiable risk factors

Arch height. A high arch (pes cavus) is associated with increased risk of running-related injury, including bone stress injury, Achilles tendinopathy, plantar fasciitis, and patellofemoral pain syndrome.⁵ The mechanism of injury is thought to be increased forefoot loading forces.¹

A review article showed that patients with pes cavus have reduced pain when using an orthosis, although there is no associated decrease in the risk of injury.⁵ To the contrary, a prospective study concluded that arch height was unrelated to increased risk of running-related injury.⁷

A study showed improvement in patellofemoral pain by having runners increase stride rate by 10%, which reduces stride length to a significant degree.

Evidence regarding flat feet (pes planus) and risk of injury is also mixed. Some studies show that pes planus is not associated with increased risk of injury in athletes.¹² A cross-sectional study in older patients showed those with pes planus morphology had a higher rate of knee pain and wearing away of medial compartment cartilage.¹³ Because this study comprised only older adults, it is not generalizable to runners—nor can conclusions be drawn about causation, given the cross-sectional nature of the study.

Although a foot orthosis can correct mechanical differences caused by pes planus morphology, there is not enough evidence to conclude that correction results in a lower rate of injury. In sum, data are mixed with regard to arch height as a risk factor for running-related injury.

Continue to: Patients with...

Patients with pes planus or pes cavus should not be discouraged from running, however. If they experience pain with running, they might benefit from a trial of arch support inserts; or consider referral to an orthotist for evaluation for a custom orthosis.

Sex. Based on a prospective cohort study, female runners have a slightly higher rate of running injury than male counterparts.⁴ Similarly, a study showed that female military members generally had a higher incidence of stress fractures than male military members—specifically, femoral shaft and neck stress fractures.¹⁴ Runners who fall in the spectrum of the female athlete triad, as described earlier, are particularly vulnerable to bone stress injury. It is reasonable, therefore, to review risk factors for injury with female runners (as it is with all runners), especially those who have sustained a prior running-related injury.

Increased Q-angle (an obsolete risk factor). The Q-angle is approximated by drawing a line from the anterior superior iliac spine to the patella and a second line from the patella to the tibial tubercle. In males, a normal Q-angle is 14°; in females, 17° (SD = 4.5°). The Q-angle can be obtained by goniometric or radiographic measurement.

An increased Q-angle had been considered an intrinsic risk factor for running injury but has not been shown to be associated with increased risk of running-related injury or patellofemoral pain syndrome.^27,28 Because the Q-angle is not a clinically relevant tool in assessing risk of injury, do not routinely measure it or include it in risk-factor counseling.

OA. Based on a systematic review of observational studies, data are inconclusive with regard to whether running contributes to, or is protective against, knee OA.¹⁵ In a large cohort study, running (1) was protective against development of hip OA and (2) decreased the risk of requiring hip replacement.²⁹ This finding was supported by animal-model research that concluded that it is inactivity that results in thinning of articular cartilage.²⁹ In addition, a systematic review of randomized controlled trials concluded that knee joint-loading exercises are not harmful to articular cartilage (this is low-quality evidence, however).¹⁶

Continue to: Given that there...

Given that there are no high-quality studies suggesting that running contributes to or exacerbates OA, patients with OA can be counseled to start or continue running as tolerated because the health benefit of running likely outweighs risk. Patients with pre-existing moderate-to-severe OA might report knee and hip pain that is already exacerbated by certain activities; if a high-impact activity, such as running, makes that pain worse, exercise counseling that you provide can be tailored to include lower-impact alternatives, such as swimming, cycling, or an elliptical workout.

CASE

In response to Ms. K’s interest in beginning an exercise regimen that includes running, you perform a complete routine pre-participation evaluation and appropriate cardiac screening. You discuss risk factors for running injury, focusing on modifiable risk factors.

High-mileage running, especially > 40 miles per week, is associated with increased risk of injury, most often of the hip and hamstring.

Ms. K is perimenopausal but reports a history of regular menstrual cycles. She eats a relatively well-balanced diet. You advise that her BMI should not restrict her from incorporating running into her fitness regimen. Also, you reassure her that she should not restrict running based on a diagnosis of OA; instead, you advise her to monitor her symptoms and reconsider her program if running makes her knee pain worse.

At this point, Ms. K is ready to run. She tells you that, based on your guidance, she feels more comfortable and safe starting a running program.

Preventing injury

After reviewing risk factors for running-­related injury with patients, encourage other evidence-based methods of reducing that risk.

Continue to: Shoes

The running shoe industry offers a variety of running shoes, from minimalist shoes to cushioned stability shoes that vary based on the amount of cushioning, level of motion control, and amount of heel-to-toe drop. With so many options, new runners might wonder which shoes can reduce their risk of injury and how they should select a pair.

Stability. A characteristic of running shoes promoted by the industry is their stability: ie, their motion control. Stability shoes are marketed to runners who overpronate and therefore limit motion to prevent overpronation. The benefit of stability shoes, or stability insoles, is unclear.³⁰ A randomized controlled trial showed that, in runners who overpronate, motion-control shoes reduced their risk of injury.³¹ However, another study assessed whether shoes that had been “prescribed” based on foot morphology and stride reduced the risk of injury (compared to neutral, cushioned shoes) and found no change in the incidence of soft-tissue injury.³² Given no strong evidence to suggest otherwise, runners can be advised to buy shoes based on comfort rather than on foot morphology or running stride.

Heel-to-toe drop. Another component of shoe variability is heel-to-toe drop (the height difference between heel and forefoot). A study suggests that moderate-to-high (8-12 mm) heel-to-toe drop is associated with a reduced risk of running injury.³³ Barefoot running shoes, which, typically, have no heel-to-toe drop, are associated with increased risk of injury—specifically, foot stress fracture (especially in runners who are even moderately overweight).^34,35

Shoe age and shoe wear can be modified to reduce injury. There is evidence that running shoes lose approximately 50% of cushioning after 300 to 500 miles of use.³⁶ Another study found that rotating running shoes—ideally, different types or brands—can lead to fewer running-related injuries.³⁷

In general, patients can be counseled to use shoes that feel comfortable, as long as they replace them regularly (TABLE 2). Runners can also consider alternating pairs of different running shoes between runs. Overweight runners should avoid minimally cushioned and low heel-to-toe drop running shoes.

Continue to: Cross-training

Cross-training exercises for runners include cycling, an elliptical workout, swimming, and weightlifting. Incorporating cross-­training can be protective against running injury because cross-training requires different movement patterns, prevents overuse, and equalizes muscle imbalances that occur with running.⁷ In addition, replacing running with a cross-training activity can decrease weekly running time and mileage, which can further reduce risk of running-related injury.⁷ Runners—especially higher-mileage runners—should be encouraged to incorporate cross-training into their workout regimen to decrease their risk of injury.

There is no reason to counsel runners to run on a softer running surface, unless they find that doing so is more comfortable.

Stretching. The authors of a Cochrane review concluded that there is no significant reduction in injury associated with hamstring or gastrocnemius stretching.³² A small randomized, controlled, crossover study concluded that participants subjectively felt their performance was better when warm-ups included stretching.³⁸ This perceived improvement in performance was similar between groups who completed dynamic or static stretching. However, no difference was noted in flexibility or objective performance between groups who stretched or did not stretch before activity.

Although there is no supporting evidence that stretching reduces the risk of injury, stretching is a low-risk intervention. Because stretching might provide subjective benefit to runners, you need not discourage patients from including this activity in their running program.

CORRESPONDENCE
Kartik Sidhar, MD, 15370 Huff Way, Brookfield, WI, 53005; [email protected]

Sarcoidosis is a multisystem inflammatory disease of unclear etiology that primarily affects the lungs. It can occur at any age but usually develops before the age of 50 years, with an initial peak incidence at 20 to 29 years and a second peak incidence after 50 years of age, especially among women in Scandinavia and Japan.¹ Sarcoidosis affects men and women of all racial and ethnic groups throughout the world, but differences based on race, sex, and geography are noted.¹

The highest rates are reported in northern European and African-American individuals, particularly in women.^1,2 The adjusted annual incidence of sarcoidosis among African Americans is approximately 3 times that among White Americans³ and is more likely to be chronic and fatal in African Americans.³ The disease can be familial with a possible recessive inheritance mode with incomplete penetrance.⁴ Risk of sarcoidosis in monozygotic twins appears to be 80 times greater than that in the general population, which supports genetic factors accounting for two-thirds of disease susceptibility.⁵

Likely factors in the development of sarcoidosis

The exact cause of sarcoidosis is unknown, but we have insights into its pathogenesis and potential triggers.^1,6-9 Genes involved are being identified: class I and II human leukocyte antigen (HLA) molecules are most consistently associated with risk of sarcoidosis. Environmental exposures can activate the innate immune system and precondition a susceptible individual to react to potential causative antigens in a highly polarized, antigen-specific Th1 immune response. The epithelioid granulomatous response involves local proinflammatory cytokine production and enhanced T-cell immunity at sites of inflammation.¹⁰ Granulomas generally form to confine pathogens, restrict inflammation, and protect surrounding tissue.^11-13

Sarcoidosis is a diagnosis of exclusion; one must rule out infections, occupational or environmental exposures, malignancies, and other disorders that cause granulomatous inflammation.

ACCESS (A Case Control Etiologic Study of Sarcoidosis) identified several environmental exposures such as chemicals used in the agriculture industry, mold or mildew, and musty odors at work.¹⁴ Tobacco use was not associated with sarcoidosis.¹⁴ Recent studies have shown positive associations with service in the US Navy,¹⁵ metal working,¹⁶ firefighting,¹⁷ the handling of building supplies,¹⁸ and onsite exposure while assisting in rescue efforts at the World Trade Center disaster.¹⁹ Other data support the likelihood that specific environmental exposures associated with microbe-rich environments modestly increase the risk of sarcoidosis.¹⁴ Mycobacterial and propionibacterial DNA and RNA are potentially associated with sarcoidosis.²⁰

Clinical manifestations are nonspecific

The diagnosis of sarcoidosis can be difficult and delayed due to diverse organ involvement and nonspecific presentations. TABLE 1^21-31 shows the diverse manifestations in a patient with suspected sarcoidosis. Around 50% of the patients are asymptomatic.^23,24 Sarcoidosis is a diagnosis of exclusion, starting with a detailed history to rule out infections, occupational or environmental exposures, malignancies, and other possible disorders (TABLE 2).²²

Diagnostic work-up

The primary objective of a diagnostic evaluation in most suspected cases of sarcoidosis is to corroborate the clinical and radiologic features with pathologic evidence of non-necrotizing granulomas and to exclude other causes of granulomatous inflammation.²²

Radiologic studies

Chest x-ray (CXR) provides diagnostic and prognostic information in the evaluation of sarcoidosis using the Scadding classification system (FIGURE 1).^21,25,32,33 Interobserver variability, especially between stages II and III and III and IV is the major limitation of this system.³² At presentation, radiographs are abnormal in approximately 90% of patients.³⁴ Lymphadenopathy is the most common radiographic abnormality, occurring in more than two-thirds of cases, and pulmonary opacities (nodules and reticulation) with a middle to upper lobe predilection are present in 20% to 50% of patients.^1,31,35 The nodules vary in size and can coalesce and cause alveolar collapse, thus producing consolidation.³⁶ Linear opacities radiating laterally from the hilum into the middle and upper zones are characteristic in fibrotic disease.

Continue to: High-resoluton computed tomography

High-resolution computed tomography (HRCT). Micronodules in a perilymphatic distribution with upper lobe predominance combined with subcarinal and symmetrical hilar lymph node enlargement is practically diagnostic of sarcoidosis in the right clinical context. TABLE 3^21,23,25,32 and FIGURE 2^21,23,25,32 summarize the common CT chest findings of sarcoidosis.

Advanced imaging such as (18)F-fluorodeoxyglucose positron emission tomography (PET) and magnetic resonance imaging (MRI) are used in specialized settings for advanced pulmonary, cardiac, or neurosarcoidosis.

Tissue biopsy

Skin lesions (other than erythema nodosum), eye lesions, and peripheral lymph nodes are considered the safest extrapulmonary locations for biopsy.^21,25 If pulmonary infiltrates or lymphadenopathy are present, or if extrapulmonary biopsy sites are not available, then flexible bronchoscopy with biopsy is the mainstay for tissue sampling.²⁵

Bronchoalveolar lavage (BAL), transbronchial biopsy (TBB), endobronchial biopsy (EBB), and endobronchial ultrasound (EBUS) are invaluable modalities that have reduced the need for open lung biopsy. BAL in sarcoidosis can show lymphocytosis > 15% (nonspecific) and a CD4:CD8 lymphocyte ratio > 3.5 (specificity > 90%).^21,22 TBB is more sensitive than EBB; however, sensitivity overall is heightened when both of them are combined. The advent of EBUS has increased the safety and efficiency of needle aspiration of mediastinal lymph nodes. Diagnostic yield of EBUS (~80%) is superior to that with TBB and EBB (~50%), especially in stage I and II sarcoidosis.³⁷ The combination of EBUS with TBB improves the diagnostic yield to ~90%.³⁷

The decision to obtain biopsy samples hinges on the nature of clinical and radiologic findings (FIGURE 3).^22,25,26

Continue to: Laboratory studies

Multiple abnormalities may be seen in sarcoidosis, and specific lab tests may help support a diagnosis of sarcoidosis or detect organ-specific disease activity (TABLE 4).^22,23,25,38 However, no consistently accurate biomarkers exist for use in clinical practice. An angiotensin-converting enzyme (ACE) level greater than 2 times the upper limit of normal may be helpful; however, sensitivity remains low, and genetic polymorphisms can influence the ACE level.²⁵ Biomarkers sometimes used to assess disease activity are serum interleukin-2 receptor, neopterin, chitotriosidase, lysozyme, KL-6 glycoprotein, and amyloid A.²¹

Additional tests to assess specific features or organ involvement

Pulmonary function testing (PFT) is reviewed in detail below under “pulmonary sarcoidosis.”

Electrocardiogram (EKG)/transthoracic echocardiogram (TTE). EKG abnormalities—conduction disturbances, arrhythmias, or nonspecific ST segment and T-wave changes—are the most common nonspecific findings.³⁰ TTE findings are also nonspecific but have value in assessing cardiac chamber size and function and myocardial involvement. TTE is indeed the most common screening modality for sarcoidosis-associated pulmonary hypertension (SAPH), which is definitively diagnosed by right heart catheterization (RHC). Further evaluation for cardiac sarcoidosis can be done with cardiac MRI or fluorodeoxyglucose PET in specialized settings.

Lumbar puncture (LP) may reveal lymphocytic infiltration in suspected neurosarcoidosis, but the finding is nonspecific and can reflect infection or malignancy. Oligoclonal bands may also be seen in about one-third of neurosarcoidosis cases, and it is imperative to rule out multiple sclerosis.²⁸

Pulmonary sarcoidosis

Pulmonary sarcoidosis accounts for most of the morbidity, mortality, and health care use associated with sarcoidosis.^39,40

Continue to: Pathology of early and advanced pulmonary sarcoidosis

Pathology of early and advanced pulmonary sarcoidosis

Sarcoidosis is characterized by coalescing, tightly clustered, nonnecrotizing granulomas in the lung (FIGURE 4), most often located along the lymphatic routes of the pleura, interlobular septa, and bronchovascular bundles.⁴¹ Granulomas contain epithelioid cells or multinucleated giant cells surrounded by a chronic lymphocytic infiltrate. Typically, intracytoplasmic inclusions, such as Schaumann bodies, asteroid bodies, and blue bodies of calcium oxalates are noted within giant cells.

In chronic disease, lymphocytic infiltrate vanishes and granulomas tend to become increasingly fibrotic and enlarge to form hyalinized nodules rich with densely eosinophilic collagen. In 10% to 30% of cases, the lungs undergo progressive fibrosis.⁴⁰ Nonresolving inflammation appears to be the major cause of fibrosis and the peribronchovascular localization leading to marked bronchial distortion.

Clinical features, monitoring, and outcomes

Pulmonary involvement occurs in most patients with sarcoidosis, and subclinical pulmonary disease is generally present, even when extrathoracic manifestations predominate.²³ Dry cough, dyspnea, and chest discomfort are the most common symptoms. Chest auscultation is usually unremarkable. Wheezing is more common in those with fibrosis and is attributed to airway-centric fibrosis.⁴² There is often a substantial delay between the onset of symptoms and the diagnosis of pulmonary sarcoidosis, as symptoms are nonspecific and might be mistaken for more common pulmonary diseases, such as asthma or chronic bronchitis.⁴³

Since sarcoidosis can affect pulmonary parenchyma, interstitium, large and small airways, pulmonary vasculature, and respiratory muscles, the pattern of lung function impairment on PFT varies from normal to obstruction, restriction, isolated diffusion defect, or a combination of these. The typical physiologic abnormality is a restrictive ventilatory defect with a decreased diffusing capacity of the lung for carbon monoxide (DLCO). Extent of disease seen on HRCT correlates with level of restriction.⁴⁴ Airway obstruction can be multifactorial and due to airway distortion (more likely to occur in fibrotic lung disease) and luminal disease.^45-48 The 6-minute walk test and DLCO can also aid in the diagnosis of SAPH and advanced parenchymal lung disease.

While monitoring is done clinically and with testing (PFT and imaging) as needed, the optimal approach is unclear. Nevertheless, longitudinal monitoring with testing may provide useful management and prognostic information.⁴⁰ Pulmonary function can remain stable in fibrotic sarcoidosis over extended periods and actually can improve in some patients.⁴⁹ Serial spirometry, particularly forced vital capacity, is the most reliable tool for monitoring; when a decline in measurement occurs, chest radiography can elucidate the mechanism.^50,51

Continue to: Because sarcoidosis is a multisystem disease...

Because sarcoidosis is a multisystem disease, caution needs to be exercised when evaluating a patient’s new or worsening respiratory symptoms to accurately determine the cause of symptoms and direct therapy accordingly. In addition to refractory inflammatory pulmonary disease, airway disease, infection, fibrosis, and SAPH, one needs to consider extrapulmonary involvement or complications such as cardiac or neurologic disease, musculoskeletal disease, depression, or fatigue. Adverse medication effects, deconditioning, or unrelated (or possibly related) disorders (eg pulmonary embolism) may be to blame.

Determining prognosis

Prognosis of sarcoidosis varies and depends on epidemiologic factors, clinical presentation, and course, as well as specific organ involvement. Patients may develop life-threatening pulmonary, cardiac, or neurologic complications. End-stage disease may require organ transplantation for eligible patients.

Most patients with pulmonary sarcoidosis experience clinical remission with minimal residual organ impairment and a favorable long-term outcome. Advanced pulmonary disease (known as APS) occurs in a small proportion of patients with sarcoidosis but accounts for most of the poor outcomes in sarcoidosis.⁴⁰ APS is variably defined, but it generally includes pulmonary fibrosis, SAPH, and respiratory infection.

One percent to 5% of patients with sarcoidosis die from complications, and mortality is higher in women and African Americans.⁵² Mortality and morbidity may be increasing.⁵³ The reasons behind these trends are unclear but could include true increases in disease incidence, better detection rates, greater severity of disease, or an aging population. Increased hospitalizations and health care use might be due to organ damage from granulomatous inflammation (and resultant fibrosis), complications associated with treatment, and psychosocial effects of the disease/treatment.

Management

Management consists primarily of anti-­inflammatory or immunosuppressive therapies but can also include measures to address specific complications (such as fatigue) and organ transplant, as well as efforts to counter adverse medication effects. Other supportive and preventive measures may include, on a case-by-case basis, oxygen supplementation, vaccinations, or pulmonary rehabilitation. Details of these are found in other, more in-depth reviews on treatment; we will briefly review anti-inflammatory therapy, which forms the cornerstone of treatment in most patients with sarcoidosis.

Continue to: General approach to treatment decisions

General approach to treatment decisions. Anti-inflammatory therapy is used to reduce granulomatous inflammation, thereby preserving organ function and reducing symptoms. A decision to begin treatment is one shared with the patient and is based on symptoms and potential danger of organ system failure.⁵⁴ Patients who are symptomatic or have progressive disease or physiologic impairment are generally candidates for treatment. Monitoring usually suffices for those who have minimal symptoms, stable disease, and preserved organ function.

Patients with pulmonary sarcoidosis at CXR stage 0 should not receive treatment, given that large, randomized trials have shown no meaningful benefit and that these patients have a high likelihood of spontaneous remission and excellent long-term prognosis.^55-58 However, a subgroup of patients classified as stage 0/I on CXR may show parenchymal disease on HRCT,⁵⁹ and, if more symptomatic, could be considered for treatment. For patients with stage II to IV pulmonary sarcoidosis with symptoms, there is good evidence that treatment may improve lung function and reduce dyspnea and fatigue.^57,60-62

Corticosteroids are first-line treatment for most patients. Based on expert opinion, treatment of pulmonary sarcoidosis is generally started with oral prednisone (or an equivalent corticosteroid). A starting dose of 20 to 40 mg/d generally is sufficient for most patients. If the patient responds to initial treatment, prednisone dose is tapered over a period of months. If symptoms worsen during tapering, the minimum effective dose is maintained without further attempts at tapering. Treatment is continued for at least 3 to 6 months but it might be needed for longer durations; unfortunately, evidence-based guidelines are lacking.⁶³ Once the patient goes into remission, close monitoring is done for possible relapses. Inhaled corticosteroids alone have not reduced symptoms or improved lung function in patients with pulmonary sarcoidosis.^64-66

Steroid-sparing agents are added for many patients. For patients receiving chronic prednisone therapy (≥ 10 mg for > 6 months), steroid-sparing agents are considered to minimize the adverse effects of steroids or to better control the inflammatory activity of sarcoidosis. These agents must be carefully selected, and clinical and laboratory monitoring need to be done throughout therapy. TABLE 5^58,64,67-81shows the major anti-inflammatory treatment agents used for sarcoidosis.

The management might be complicated for extrapulmonary, multi-organ, and advanced sarcoidosis (advanced pulmonary sarcoidosis, cardiac disease, neurosarcoidosis, lupus pernio, etc) when specialized testing, as well as a combination of corticosteroids and steroid-sparing agents (with higher doses or prolonged courses), might be needed. This should be performed at an expert sarcoidosis center, ideally in a multidisciplinary setting involving pulmonologists and/or rheumatologists, chest radiologists, and specialists as indicated, based on specific organ involvement.

Continue to: Research and future directions

Research and future directions

Key goals for research are identifying more accurate biomarkers of disease, improving diagnosis of multi-organ disease, determining validated endpoints of clinical trials in sarcoidosis, and developing treatments for refractory cases.

There is optimism and opportunity in the field of sarcoidosis overall. An example of an advancement is in the area of APS, as the severity and importance of this phenotype has been better understood. Worldwide registries and trials of pulmonary vasodilator therapy (bosentan, sildenafil, epoprostenol, and inhaled iloprost) in patients with SAPH without left ventricular dysfunction are promising.^82-85 However, no benefit in survival has been shown.

RioSAPH is a double-blind, placebo-controlled trial of Riociguat (a stimulator of soluble guanylate cyclase) for SAPH (NCT02625558) that is closed to enrollment and undergoing data review. Similarly, results of the phase IV study of pirfenidone, an antifibrotic agent that was shown to decrease disease progression and deaths in idiopathic pulmonary fibrosis,⁸⁶ are awaited in the near future.

Other potential directions being explored are multicenter patient registries and randomized controlled trials, analyses of existing databases, use of biobanking, and patient-centered outcome measures. Hopefully, the care of patients with sarcoidosis will become more evidence based with ongoing and upcoming research in this field.

CORRESPONDENCE
Rohit Gupta, MBBS, FCCP, 3401 North Broad Street, 7 Parkinson Pavilion, Philadelphia, PA 19140; [email protected]

Sarcoidosis is a multisystem inflammatory disease of unclear etiology that primarily affects the lungs. It can occur at any age but usually develops before the age of 50 years, with an initial peak incidence at 20 to 29 years and a second peak incidence after 50 years of age, especially among women in Scandinavia and Japan.¹ Sarcoidosis affects men and women of all racial and ethnic groups throughout the world, but differences based on race, sex, and geography are noted.¹

The highest rates are reported in northern European and African-American individuals, particularly in women.^1,2 The adjusted annual incidence of sarcoidosis among African Americans is approximately 3 times that among White Americans³ and is more likely to be chronic and fatal in African Americans.³ The disease can be familial with a possible recessive inheritance mode with incomplete penetrance.⁴ Risk of sarcoidosis in monozygotic twins appears to be 80 times greater than that in the general population, which supports genetic factors accounting for two-thirds of disease susceptibility.⁵

Likely factors in the development of sarcoidosis

The exact cause of sarcoidosis is unknown, but we have insights into its pathogenesis and potential triggers.^1,6-9 Genes involved are being identified: class I and II human leukocyte antigen (HLA) molecules are most consistently associated with risk of sarcoidosis. Environmental exposures can activate the innate immune system and precondition a susceptible individual to react to potential causative antigens in a highly polarized, antigen-specific Th1 immune response. The epithelioid granulomatous response involves local proinflammatory cytokine production and enhanced T-cell immunity at sites of inflammation.¹⁰ Granulomas generally form to confine pathogens, restrict inflammation, and protect surrounding tissue.^11-13

Sarcoidosis is a diagnosis of exclusion; one must rule out infections, occupational or environmental exposures, malignancies, and other disorders that cause granulomatous inflammation.

ACCESS (A Case Control Etiologic Study of Sarcoidosis) identified several environmental exposures such as chemicals used in the agriculture industry, mold or mildew, and musty odors at work.¹⁴ Tobacco use was not associated with sarcoidosis.¹⁴ Recent studies have shown positive associations with service in the US Navy,¹⁵ metal working,¹⁶ firefighting,¹⁷ the handling of building supplies,¹⁸ and onsite exposure while assisting in rescue efforts at the World Trade Center disaster.¹⁹ Other data support the likelihood that specific environmental exposures associated with microbe-rich environments modestly increase the risk of sarcoidosis.¹⁴ Mycobacterial and propionibacterial DNA and RNA are potentially associated with sarcoidosis.²⁰

Clinical manifestations are nonspecific

The diagnosis of sarcoidosis can be difficult and delayed due to diverse organ involvement and nonspecific presentations. TABLE 1^21-31 shows the diverse manifestations in a patient with suspected sarcoidosis. Around 50% of the patients are asymptomatic.^23,24 Sarcoidosis is a diagnosis of exclusion, starting with a detailed history to rule out infections, occupational or environmental exposures, malignancies, and other possible disorders (TABLE 2).²²

Diagnostic work-up

The primary objective of a diagnostic evaluation in most suspected cases of sarcoidosis is to corroborate the clinical and radiologic features with pathologic evidence of non-necrotizing granulomas and to exclude other causes of granulomatous inflammation.²²

Radiologic studies

Chest x-ray (CXR) provides diagnostic and prognostic information in the evaluation of sarcoidosis using the Scadding classification system (FIGURE 1).^21,25,32,33 Interobserver variability, especially between stages II and III and III and IV is the major limitation of this system.³² At presentation, radiographs are abnormal in approximately 90% of patients.³⁴ Lymphadenopathy is the most common radiographic abnormality, occurring in more than two-thirds of cases, and pulmonary opacities (nodules and reticulation) with a middle to upper lobe predilection are present in 20% to 50% of patients.^1,31,35 The nodules vary in size and can coalesce and cause alveolar collapse, thus producing consolidation.³⁶ Linear opacities radiating laterally from the hilum into the middle and upper zones are characteristic in fibrotic disease.

Continue to: High-resoluton computed tomography

High-resolution computed tomography (HRCT). Micronodules in a perilymphatic distribution with upper lobe predominance combined with subcarinal and symmetrical hilar lymph node enlargement is practically diagnostic of sarcoidosis in the right clinical context. TABLE 3^21,23,25,32 and FIGURE 2^21,23,25,32 summarize the common CT chest findings of sarcoidosis.

Advanced imaging such as (18)F-fluorodeoxyglucose positron emission tomography (PET) and magnetic resonance imaging (MRI) are used in specialized settings for advanced pulmonary, cardiac, or neurosarcoidosis.

Tissue biopsy

Skin lesions (other than erythema nodosum), eye lesions, and peripheral lymph nodes are considered the safest extrapulmonary locations for biopsy.^21,25 If pulmonary infiltrates or lymphadenopathy are present, or if extrapulmonary biopsy sites are not available, then flexible bronchoscopy with biopsy is the mainstay for tissue sampling.²⁵

Bronchoalveolar lavage (BAL), transbronchial biopsy (TBB), endobronchial biopsy (EBB), and endobronchial ultrasound (EBUS) are invaluable modalities that have reduced the need for open lung biopsy. BAL in sarcoidosis can show lymphocytosis > 15% (nonspecific) and a CD4:CD8 lymphocyte ratio > 3.5 (specificity > 90%).^21,22 TBB is more sensitive than EBB; however, sensitivity overall is heightened when both of them are combined. The advent of EBUS has increased the safety and efficiency of needle aspiration of mediastinal lymph nodes. Diagnostic yield of EBUS (~80%) is superior to that with TBB and EBB (~50%), especially in stage I and II sarcoidosis.³⁷ The combination of EBUS with TBB improves the diagnostic yield to ~90%.³⁷

The decision to obtain biopsy samples hinges on the nature of clinical and radiologic findings (FIGURE 3).^22,25,26

Continue to: Laboratory studies

Multiple abnormalities may be seen in sarcoidosis, and specific lab tests may help support a diagnosis of sarcoidosis or detect organ-specific disease activity (TABLE 4).^22,23,25,38 However, no consistently accurate biomarkers exist for use in clinical practice. An angiotensin-converting enzyme (ACE) level greater than 2 times the upper limit of normal may be helpful; however, sensitivity remains low, and genetic polymorphisms can influence the ACE level.²⁵ Biomarkers sometimes used to assess disease activity are serum interleukin-2 receptor, neopterin, chitotriosidase, lysozyme, KL-6 glycoprotein, and amyloid A.²¹

Additional tests to assess specific features or organ involvement

Pulmonary function testing (PFT) is reviewed in detail below under “pulmonary sarcoidosis.”

Electrocardiogram (EKG)/transthoracic echocardiogram (TTE). EKG abnormalities—conduction disturbances, arrhythmias, or nonspecific ST segment and T-wave changes—are the most common nonspecific findings.³⁰ TTE findings are also nonspecific but have value in assessing cardiac chamber size and function and myocardial involvement. TTE is indeed the most common screening modality for sarcoidosis-associated pulmonary hypertension (SAPH), which is definitively diagnosed by right heart catheterization (RHC). Further evaluation for cardiac sarcoidosis can be done with cardiac MRI or fluorodeoxyglucose PET in specialized settings.

Lumbar puncture (LP) may reveal lymphocytic infiltration in suspected neurosarcoidosis, but the finding is nonspecific and can reflect infection or malignancy. Oligoclonal bands may also be seen in about one-third of neurosarcoidosis cases, and it is imperative to rule out multiple sclerosis.²⁸

Pulmonary sarcoidosis

Pulmonary sarcoidosis accounts for most of the morbidity, mortality, and health care use associated with sarcoidosis.^39,40

Continue to: Pathology of early and advanced pulmonary sarcoidosis

Pathology of early and advanced pulmonary sarcoidosis

Sarcoidosis is characterized by coalescing, tightly clustered, nonnecrotizing granulomas in the lung (FIGURE 4), most often located along the lymphatic routes of the pleura, interlobular septa, and bronchovascular bundles.⁴¹ Granulomas contain epithelioid cells or multinucleated giant cells surrounded by a chronic lymphocytic infiltrate. Typically, intracytoplasmic inclusions, such as Schaumann bodies, asteroid bodies, and blue bodies of calcium oxalates are noted within giant cells.

In chronic disease, lymphocytic infiltrate vanishes and granulomas tend to become increasingly fibrotic and enlarge to form hyalinized nodules rich with densely eosinophilic collagen. In 10% to 30% of cases, the lungs undergo progressive fibrosis.⁴⁰ Nonresolving inflammation appears to be the major cause of fibrosis and the peribronchovascular localization leading to marked bronchial distortion.

Clinical features, monitoring, and outcomes

Pulmonary involvement occurs in most patients with sarcoidosis, and subclinical pulmonary disease is generally present, even when extrathoracic manifestations predominate.²³ Dry cough, dyspnea, and chest discomfort are the most common symptoms. Chest auscultation is usually unremarkable. Wheezing is more common in those with fibrosis and is attributed to airway-centric fibrosis.⁴² There is often a substantial delay between the onset of symptoms and the diagnosis of pulmonary sarcoidosis, as symptoms are nonspecific and might be mistaken for more common pulmonary diseases, such as asthma or chronic bronchitis.⁴³

Since sarcoidosis can affect pulmonary parenchyma, interstitium, large and small airways, pulmonary vasculature, and respiratory muscles, the pattern of lung function impairment on PFT varies from normal to obstruction, restriction, isolated diffusion defect, or a combination of these. The typical physiologic abnormality is a restrictive ventilatory defect with a decreased diffusing capacity of the lung for carbon monoxide (DLCO). Extent of disease seen on HRCT correlates with level of restriction.⁴⁴ Airway obstruction can be multifactorial and due to airway distortion (more likely to occur in fibrotic lung disease) and luminal disease.^45-48 The 6-minute walk test and DLCO can also aid in the diagnosis of SAPH and advanced parenchymal lung disease.

While monitoring is done clinically and with testing (PFT and imaging) as needed, the optimal approach is unclear. Nevertheless, longitudinal monitoring with testing may provide useful management and prognostic information.⁴⁰ Pulmonary function can remain stable in fibrotic sarcoidosis over extended periods and actually can improve in some patients.⁴⁹ Serial spirometry, particularly forced vital capacity, is the most reliable tool for monitoring; when a decline in measurement occurs, chest radiography can elucidate the mechanism.^50,51

Continue to: Because sarcoidosis is a multisystem disease...

Because sarcoidosis is a multisystem disease, caution needs to be exercised when evaluating a patient’s new or worsening respiratory symptoms to accurately determine the cause of symptoms and direct therapy accordingly. In addition to refractory inflammatory pulmonary disease, airway disease, infection, fibrosis, and SAPH, one needs to consider extrapulmonary involvement or complications such as cardiac or neurologic disease, musculoskeletal disease, depression, or fatigue. Adverse medication effects, deconditioning, or unrelated (or possibly related) disorders (eg pulmonary embolism) may be to blame.

Determining prognosis

Prognosis of sarcoidosis varies and depends on epidemiologic factors, clinical presentation, and course, as well as specific organ involvement. Patients may develop life-threatening pulmonary, cardiac, or neurologic complications. End-stage disease may require organ transplantation for eligible patients.

Most patients with pulmonary sarcoidosis experience clinical remission with minimal residual organ impairment and a favorable long-term outcome. Advanced pulmonary disease (known as APS) occurs in a small proportion of patients with sarcoidosis but accounts for most of the poor outcomes in sarcoidosis.⁴⁰ APS is variably defined, but it generally includes pulmonary fibrosis, SAPH, and respiratory infection.

One percent to 5% of patients with sarcoidosis die from complications, and mortality is higher in women and African Americans.⁵² Mortality and morbidity may be increasing.⁵³ The reasons behind these trends are unclear but could include true increases in disease incidence, better detection rates, greater severity of disease, or an aging population. Increased hospitalizations and health care use might be due to organ damage from granulomatous inflammation (and resultant fibrosis), complications associated with treatment, and psychosocial effects of the disease/treatment.

Management

Management consists primarily of anti-­inflammatory or immunosuppressive therapies but can also include measures to address specific complications (such as fatigue) and organ transplant, as well as efforts to counter adverse medication effects. Other supportive and preventive measures may include, on a case-by-case basis, oxygen supplementation, vaccinations, or pulmonary rehabilitation. Details of these are found in other, more in-depth reviews on treatment; we will briefly review anti-inflammatory therapy, which forms the cornerstone of treatment in most patients with sarcoidosis.

Continue to: General approach to treatment decisions

General approach to treatment decisions. Anti-inflammatory therapy is used to reduce granulomatous inflammation, thereby preserving organ function and reducing symptoms. A decision to begin treatment is one shared with the patient and is based on symptoms and potential danger of organ system failure.⁵⁴ Patients who are symptomatic or have progressive disease or physiologic impairment are generally candidates for treatment. Monitoring usually suffices for those who have minimal symptoms, stable disease, and preserved organ function.

Patients with pulmonary sarcoidosis at CXR stage 0 should not receive treatment, given that large, randomized trials have shown no meaningful benefit and that these patients have a high likelihood of spontaneous remission and excellent long-term prognosis.^55-58 However, a subgroup of patients classified as stage 0/I on CXR may show parenchymal disease on HRCT,⁵⁹ and, if more symptomatic, could be considered for treatment. For patients with stage II to IV pulmonary sarcoidosis with symptoms, there is good evidence that treatment may improve lung function and reduce dyspnea and fatigue.^57,60-62

Corticosteroids are first-line treatment for most patients. Based on expert opinion, treatment of pulmonary sarcoidosis is generally started with oral prednisone (or an equivalent corticosteroid). A starting dose of 20 to 40 mg/d generally is sufficient for most patients. If the patient responds to initial treatment, prednisone dose is tapered over a period of months. If symptoms worsen during tapering, the minimum effective dose is maintained without further attempts at tapering. Treatment is continued for at least 3 to 6 months but it might be needed for longer durations; unfortunately, evidence-based guidelines are lacking.⁶³ Once the patient goes into remission, close monitoring is done for possible relapses. Inhaled corticosteroids alone have not reduced symptoms or improved lung function in patients with pulmonary sarcoidosis.^64-66

Steroid-sparing agents are added for many patients. For patients receiving chronic prednisone therapy (≥ 10 mg for > 6 months), steroid-sparing agents are considered to minimize the adverse effects of steroids or to better control the inflammatory activity of sarcoidosis. These agents must be carefully selected, and clinical and laboratory monitoring need to be done throughout therapy. TABLE 5^58,64,67-81shows the major anti-inflammatory treatment agents used for sarcoidosis.

The management might be complicated for extrapulmonary, multi-organ, and advanced sarcoidosis (advanced pulmonary sarcoidosis, cardiac disease, neurosarcoidosis, lupus pernio, etc) when specialized testing, as well as a combination of corticosteroids and steroid-sparing agents (with higher doses or prolonged courses), might be needed. This should be performed at an expert sarcoidosis center, ideally in a multidisciplinary setting involving pulmonologists and/or rheumatologists, chest radiologists, and specialists as indicated, based on specific organ involvement.

Continue to: Research and future directions

Research and future directions

Key goals for research are identifying more accurate biomarkers of disease, improving diagnosis of multi-organ disease, determining validated endpoints of clinical trials in sarcoidosis, and developing treatments for refractory cases.

There is optimism and opportunity in the field of sarcoidosis overall. An example of an advancement is in the area of APS, as the severity and importance of this phenotype has been better understood. Worldwide registries and trials of pulmonary vasodilator therapy (bosentan, sildenafil, epoprostenol, and inhaled iloprost) in patients with SAPH without left ventricular dysfunction are promising.^82-85 However, no benefit in survival has been shown.

RioSAPH is a double-blind, placebo-controlled trial of Riociguat (a stimulator of soluble guanylate cyclase) for SAPH (NCT02625558) that is closed to enrollment and undergoing data review. Similarly, results of the phase IV study of pirfenidone, an antifibrotic agent that was shown to decrease disease progression and deaths in idiopathic pulmonary fibrosis,⁸⁶ are awaited in the near future.

Other potential directions being explored are multicenter patient registries and randomized controlled trials, analyses of existing databases, use of biobanking, and patient-centered outcome measures. Hopefully, the care of patients with sarcoidosis will become more evidence based with ongoing and upcoming research in this field.

CORRESPONDENCE
Rohit Gupta, MBBS, FCCP, 3401 North Broad Street, 7 Parkinson Pavilion, Philadelphia, PA 19140; [email protected]

Sarcoidosis is a multisystem inflammatory disease of unclear etiology that primarily affects the lungs. It can occur at any age but usually develops before the age of 50 years, with an initial peak incidence at 20 to 29 years and a second peak incidence after 50 years of age, especially among women in Scandinavia and Japan.¹ Sarcoidosis affects men and women of all racial and ethnic groups throughout the world, but differences based on race, sex, and geography are noted.¹

The highest rates are reported in northern European and African-American individuals, particularly in women.^1,2 The adjusted annual incidence of sarcoidosis among African Americans is approximately 3 times that among White Americans³ and is more likely to be chronic and fatal in African Americans.³ The disease can be familial with a possible recessive inheritance mode with incomplete penetrance.⁴ Risk of sarcoidosis in monozygotic twins appears to be 80 times greater than that in the general population, which supports genetic factors accounting for two-thirds of disease susceptibility.⁵

Likely factors in the development of sarcoidosis

The exact cause of sarcoidosis is unknown, but we have insights into its pathogenesis and potential triggers.^1,6-9 Genes involved are being identified: class I and II human leukocyte antigen (HLA) molecules are most consistently associated with risk of sarcoidosis. Environmental exposures can activate the innate immune system and precondition a susceptible individual to react to potential causative antigens in a highly polarized, antigen-specific Th1 immune response. The epithelioid granulomatous response involves local proinflammatory cytokine production and enhanced T-cell immunity at sites of inflammation.¹⁰ Granulomas generally form to confine pathogens, restrict inflammation, and protect surrounding tissue.^11-13

Sarcoidosis is a diagnosis of exclusion; one must rule out infections, occupational or environmental exposures, malignancies, and other disorders that cause granulomatous inflammation.

ACCESS (A Case Control Etiologic Study of Sarcoidosis) identified several environmental exposures such as chemicals used in the agriculture industry, mold or mildew, and musty odors at work.¹⁴ Tobacco use was not associated with sarcoidosis.¹⁴ Recent studies have shown positive associations with service in the US Navy,¹⁵ metal working,¹⁶ firefighting,¹⁷ the handling of building supplies,¹⁸ and onsite exposure while assisting in rescue efforts at the World Trade Center disaster.¹⁹ Other data support the likelihood that specific environmental exposures associated with microbe-rich environments modestly increase the risk of sarcoidosis.¹⁴ Mycobacterial and propionibacterial DNA and RNA are potentially associated with sarcoidosis.²⁰

Clinical manifestations are nonspecific

The diagnosis of sarcoidosis can be difficult and delayed due to diverse organ involvement and nonspecific presentations. TABLE 1^21-31 shows the diverse manifestations in a patient with suspected sarcoidosis. Around 50% of the patients are asymptomatic.^23,24 Sarcoidosis is a diagnosis of exclusion, starting with a detailed history to rule out infections, occupational or environmental exposures, malignancies, and other possible disorders (TABLE 2).²²

Diagnostic work-up

The primary objective of a diagnostic evaluation in most suspected cases of sarcoidosis is to corroborate the clinical and radiologic features with pathologic evidence of non-necrotizing granulomas and to exclude other causes of granulomatous inflammation.²²

Radiologic studies

Chest x-ray (CXR) provides diagnostic and prognostic information in the evaluation of sarcoidosis using the Scadding classification system (FIGURE 1).^21,25,32,33 Interobserver variability, especially between stages II and III and III and IV is the major limitation of this system.³² At presentation, radiographs are abnormal in approximately 90% of patients.³⁴ Lymphadenopathy is the most common radiographic abnormality, occurring in more than two-thirds of cases, and pulmonary opacities (nodules and reticulation) with a middle to upper lobe predilection are present in 20% to 50% of patients.^1,31,35 The nodules vary in size and can coalesce and cause alveolar collapse, thus producing consolidation.³⁶ Linear opacities radiating laterally from the hilum into the middle and upper zones are characteristic in fibrotic disease.

Continue to: High-resoluton computed tomography

High-resolution computed tomography (HRCT). Micronodules in a perilymphatic distribution with upper lobe predominance combined with subcarinal and symmetrical hilar lymph node enlargement is practically diagnostic of sarcoidosis in the right clinical context. TABLE 3^21,23,25,32 and FIGURE 2^21,23,25,32 summarize the common CT chest findings of sarcoidosis.

Advanced imaging such as (18)F-fluorodeoxyglucose positron emission tomography (PET) and magnetic resonance imaging (MRI) are used in specialized settings for advanced pulmonary, cardiac, or neurosarcoidosis.

Tissue biopsy

Skin lesions (other than erythema nodosum), eye lesions, and peripheral lymph nodes are considered the safest extrapulmonary locations for biopsy.^21,25 If pulmonary infiltrates or lymphadenopathy are present, or if extrapulmonary biopsy sites are not available, then flexible bronchoscopy with biopsy is the mainstay for tissue sampling.²⁵

Bronchoalveolar lavage (BAL), transbronchial biopsy (TBB), endobronchial biopsy (EBB), and endobronchial ultrasound (EBUS) are invaluable modalities that have reduced the need for open lung biopsy. BAL in sarcoidosis can show lymphocytosis > 15% (nonspecific) and a CD4:CD8 lymphocyte ratio > 3.5 (specificity > 90%).^21,22 TBB is more sensitive than EBB; however, sensitivity overall is heightened when both of them are combined. The advent of EBUS has increased the safety and efficiency of needle aspiration of mediastinal lymph nodes. Diagnostic yield of EBUS (~80%) is superior to that with TBB and EBB (~50%), especially in stage I and II sarcoidosis.³⁷ The combination of EBUS with TBB improves the diagnostic yield to ~90%.³⁷

The decision to obtain biopsy samples hinges on the nature of clinical and radiologic findings (FIGURE 3).^22,25,26

Continue to: Laboratory studies

Multiple abnormalities may be seen in sarcoidosis, and specific lab tests may help support a diagnosis of sarcoidosis or detect organ-specific disease activity (TABLE 4).^22,23,25,38 However, no consistently accurate biomarkers exist for use in clinical practice. An angiotensin-converting enzyme (ACE) level greater than 2 times the upper limit of normal may be helpful; however, sensitivity remains low, and genetic polymorphisms can influence the ACE level.²⁵ Biomarkers sometimes used to assess disease activity are serum interleukin-2 receptor, neopterin, chitotriosidase, lysozyme, KL-6 glycoprotein, and amyloid A.²¹

Additional tests to assess specific features or organ involvement

Pulmonary function testing (PFT) is reviewed in detail below under “pulmonary sarcoidosis.”

Electrocardiogram (EKG)/transthoracic echocardiogram (TTE). EKG abnormalities—conduction disturbances, arrhythmias, or nonspecific ST segment and T-wave changes—are the most common nonspecific findings.³⁰ TTE findings are also nonspecific but have value in assessing cardiac chamber size and function and myocardial involvement. TTE is indeed the most common screening modality for sarcoidosis-associated pulmonary hypertension (SAPH), which is definitively diagnosed by right heart catheterization (RHC). Further evaluation for cardiac sarcoidosis can be done with cardiac MRI or fluorodeoxyglucose PET in specialized settings.

Lumbar puncture (LP) may reveal lymphocytic infiltration in suspected neurosarcoidosis, but the finding is nonspecific and can reflect infection or malignancy. Oligoclonal bands may also be seen in about one-third of neurosarcoidosis cases, and it is imperative to rule out multiple sclerosis.²⁸

Pulmonary sarcoidosis

Pulmonary sarcoidosis accounts for most of the morbidity, mortality, and health care use associated with sarcoidosis.^39,40

Continue to: Pathology of early and advanced pulmonary sarcoidosis

Pathology of early and advanced pulmonary sarcoidosis

Sarcoidosis is characterized by coalescing, tightly clustered, nonnecrotizing granulomas in the lung (FIGURE 4), most often located along the lymphatic routes of the pleura, interlobular septa, and bronchovascular bundles.⁴¹ Granulomas contain epithelioid cells or multinucleated giant cells surrounded by a chronic lymphocytic infiltrate. Typically, intracytoplasmic inclusions, such as Schaumann bodies, asteroid bodies, and blue bodies of calcium oxalates are noted within giant cells.

In chronic disease, lymphocytic infiltrate vanishes and granulomas tend to become increasingly fibrotic and enlarge to form hyalinized nodules rich with densely eosinophilic collagen. In 10% to 30% of cases, the lungs undergo progressive fibrosis.⁴⁰ Nonresolving inflammation appears to be the major cause of fibrosis and the peribronchovascular localization leading to marked bronchial distortion.

Clinical features, monitoring, and outcomes

Pulmonary involvement occurs in most patients with sarcoidosis, and subclinical pulmonary disease is generally present, even when extrathoracic manifestations predominate.²³ Dry cough, dyspnea, and chest discomfort are the most common symptoms. Chest auscultation is usually unremarkable. Wheezing is more common in those with fibrosis and is attributed to airway-centric fibrosis.⁴² There is often a substantial delay between the onset of symptoms and the diagnosis of pulmonary sarcoidosis, as symptoms are nonspecific and might be mistaken for more common pulmonary diseases, such as asthma or chronic bronchitis.⁴³

Since sarcoidosis can affect pulmonary parenchyma, interstitium, large and small airways, pulmonary vasculature, and respiratory muscles, the pattern of lung function impairment on PFT varies from normal to obstruction, restriction, isolated diffusion defect, or a combination of these. The typical physiologic abnormality is a restrictive ventilatory defect with a decreased diffusing capacity of the lung for carbon monoxide (DLCO). Extent of disease seen on HRCT correlates with level of restriction.⁴⁴ Airway obstruction can be multifactorial and due to airway distortion (more likely to occur in fibrotic lung disease) and luminal disease.^45-48 The 6-minute walk test and DLCO can also aid in the diagnosis of SAPH and advanced parenchymal lung disease.

While monitoring is done clinically and with testing (PFT and imaging) as needed, the optimal approach is unclear. Nevertheless, longitudinal monitoring with testing may provide useful management and prognostic information.⁴⁰ Pulmonary function can remain stable in fibrotic sarcoidosis over extended periods and actually can improve in some patients.⁴⁹ Serial spirometry, particularly forced vital capacity, is the most reliable tool for monitoring; when a decline in measurement occurs, chest radiography can elucidate the mechanism.^50,51

Continue to: Because sarcoidosis is a multisystem disease...

Because sarcoidosis is a multisystem disease, caution needs to be exercised when evaluating a patient’s new or worsening respiratory symptoms to accurately determine the cause of symptoms and direct therapy accordingly. In addition to refractory inflammatory pulmonary disease, airway disease, infection, fibrosis, and SAPH, one needs to consider extrapulmonary involvement or complications such as cardiac or neurologic disease, musculoskeletal disease, depression, or fatigue. Adverse medication effects, deconditioning, or unrelated (or possibly related) disorders (eg pulmonary embolism) may be to blame.

Determining prognosis

Prognosis of sarcoidosis varies and depends on epidemiologic factors, clinical presentation, and course, as well as specific organ involvement. Patients may develop life-threatening pulmonary, cardiac, or neurologic complications. End-stage disease may require organ transplantation for eligible patients.

Most patients with pulmonary sarcoidosis experience clinical remission with minimal residual organ impairment and a favorable long-term outcome. Advanced pulmonary disease (known as APS) occurs in a small proportion of patients with sarcoidosis but accounts for most of the poor outcomes in sarcoidosis.⁴⁰ APS is variably defined, but it generally includes pulmonary fibrosis, SAPH, and respiratory infection.

One percent to 5% of patients with sarcoidosis die from complications, and mortality is higher in women and African Americans.⁵² Mortality and morbidity may be increasing.⁵³ The reasons behind these trends are unclear but could include true increases in disease incidence, better detection rates, greater severity of disease, or an aging population. Increased hospitalizations and health care use might be due to organ damage from granulomatous inflammation (and resultant fibrosis), complications associated with treatment, and psychosocial effects of the disease/treatment.

Management

Management consists primarily of anti-­inflammatory or immunosuppressive therapies but can also include measures to address specific complications (such as fatigue) and organ transplant, as well as efforts to counter adverse medication effects. Other supportive and preventive measures may include, on a case-by-case basis, oxygen supplementation, vaccinations, or pulmonary rehabilitation. Details of these are found in other, more in-depth reviews on treatment; we will briefly review anti-inflammatory therapy, which forms the cornerstone of treatment in most patients with sarcoidosis.

Continue to: General approach to treatment decisions

General approach to treatment decisions. Anti-inflammatory therapy is used to reduce granulomatous inflammation, thereby preserving organ function and reducing symptoms. A decision to begin treatment is one shared with the patient and is based on symptoms and potential danger of organ system failure.⁵⁴ Patients who are symptomatic or have progressive disease or physiologic impairment are generally candidates for treatment. Monitoring usually suffices for those who have minimal symptoms, stable disease, and preserved organ function.

Patients with pulmonary sarcoidosis at CXR stage 0 should not receive treatment, given that large, randomized trials have shown no meaningful benefit and that these patients have a high likelihood of spontaneous remission and excellent long-term prognosis.^55-58 However, a subgroup of patients classified as stage 0/I on CXR may show parenchymal disease on HRCT,⁵⁹ and, if more symptomatic, could be considered for treatment. For patients with stage II to IV pulmonary sarcoidosis with symptoms, there is good evidence that treatment may improve lung function and reduce dyspnea and fatigue.^57,60-62

Corticosteroids are first-line treatment for most patients. Based on expert opinion, treatment of pulmonary sarcoidosis is generally started with oral prednisone (or an equivalent corticosteroid). A starting dose of 20 to 40 mg/d generally is sufficient for most patients. If the patient responds to initial treatment, prednisone dose is tapered over a period of months. If symptoms worsen during tapering, the minimum effective dose is maintained without further attempts at tapering. Treatment is continued for at least 3 to 6 months but it might be needed for longer durations; unfortunately, evidence-based guidelines are lacking.⁶³ Once the patient goes into remission, close monitoring is done for possible relapses. Inhaled corticosteroids alone have not reduced symptoms or improved lung function in patients with pulmonary sarcoidosis.^64-66

Steroid-sparing agents are added for many patients. For patients receiving chronic prednisone therapy (≥ 10 mg for > 6 months), steroid-sparing agents are considered to minimize the adverse effects of steroids or to better control the inflammatory activity of sarcoidosis. These agents must be carefully selected, and clinical and laboratory monitoring need to be done throughout therapy. TABLE 5^58,64,67-81shows the major anti-inflammatory treatment agents used for sarcoidosis.

The management might be complicated for extrapulmonary, multi-organ, and advanced sarcoidosis (advanced pulmonary sarcoidosis, cardiac disease, neurosarcoidosis, lupus pernio, etc) when specialized testing, as well as a combination of corticosteroids and steroid-sparing agents (with higher doses or prolonged courses), might be needed. This should be performed at an expert sarcoidosis center, ideally in a multidisciplinary setting involving pulmonologists and/or rheumatologists, chest radiologists, and specialists as indicated, based on specific organ involvement.

Continue to: Research and future directions

Research and future directions

Key goals for research are identifying more accurate biomarkers of disease, improving diagnosis of multi-organ disease, determining validated endpoints of clinical trials in sarcoidosis, and developing treatments for refractory cases.

There is optimism and opportunity in the field of sarcoidosis overall. An example of an advancement is in the area of APS, as the severity and importance of this phenotype has been better understood. Worldwide registries and trials of pulmonary vasodilator therapy (bosentan, sildenafil, epoprostenol, and inhaled iloprost) in patients with SAPH without left ventricular dysfunction are promising.^82-85 However, no benefit in survival has been shown.

RioSAPH is a double-blind, placebo-controlled trial of Riociguat (a stimulator of soluble guanylate cyclase) for SAPH (NCT02625558) that is closed to enrollment and undergoing data review. Similarly, results of the phase IV study of pirfenidone, an antifibrotic agent that was shown to decrease disease progression and deaths in idiopathic pulmonary fibrosis,⁸⁶ are awaited in the near future.

Other potential directions being explored are multicenter patient registries and randomized controlled trials, analyses of existing databases, use of biobanking, and patient-centered outcome measures. Hopefully, the care of patients with sarcoidosis will become more evidence based with ongoing and upcoming research in this field.

CORRESPONDENCE
Rohit Gupta, MBBS, FCCP, 3401 North Broad Street, 7 Parkinson Pavilion, Philadelphia, PA 19140; [email protected]

In 2015-2016, almost 40% of adults and 18.5% of children ages 2 to 19 years in the United States met the definition for obesity—a chronic, relapsing, multifactorial, neurobehavioral disease that results in adverse metabolic, biomechanical, and psychosocial health consequences.^1,2

Tremendous resources have been invested in research, policy development, and public education to try to prevent obesity and its related complications. Despite this, the obesity epidemic has worsened. Here, we explore how to evaluate and treat obese patients in a primary care setting based on the evidence and our experience seeing patients specifically for weight management in a family medicine residency teaching clinic. Pharmacotherapy and surgery, while often helpful, are outside the scope of this article.

It begins withan obesity-friendly office

Patients may have reservations about health care interactions specific to obesity, so it is important to invite them into a setting that facilitates trust and encourages collaboration. Actively engage patients with unhealthy weight by creating an environment where they feel comfortable. Offer wide chairs without armrests, which will easily accommodate patients of all sizes, and ensure that scales have a weight capacity > 400 lb. Communicate a message to patients, via waiting room materials and videos, that focuses on health rather than on weight or body mass index (BMI).

Understand the patient’s goals and challenges

Most (although not all) family physicians will see obese patients in the context of a visit for diabetes, hypertension, or another condition. However, we feel that having visits specifically to address weight in the initial stages of weight management is helpful. The focus of an initial visit should be getting to know how obesity has affected the patient and what his or her motive is in attempting to lose weight. Explore previous attempts at weight loss and establish what the patient’s highest weight has been, as this will impact weight-loss goals. For example, if a patient has weighed > 300 lb all her adult life, it will be extremely difficult to maintain a weight loss of 150 lb.

What else to ask about. Discuss stressors that may be causing increased food intake or poor food choices, including hunger, anger, loneliness, and sleep difficulties. Multidisciplinary care including a psychologist can aid in addressing these issues. Ask patients if they keep a food diary (and if not, recommend that they start), as food diaries are often helpful in elucidating eating and drinking patterns. Determine a patient’s current and past levels of physical activity, as this will guide the fitness goals you develop for him or her.

Screen for psychosocial disorders

As noted earlier, the physical component of obesity is commonly associated with mood disorders such as anxiety and depression.² This requires a multidisciplinary team effort to facilitate healing in the patient struggling with obesity.

Screening for depression and anxiety using standardized tools such as the Patient Health Questionnaire-9 or the Generalized Anxiety Disorder-7 is encouraged in patients who are overweight or obese. Positive screens should be addressed as part of the patient’s treatment plan, as untreated depression and anxiety can inhibit success with weight loss. Be mindful that many medications commonly used to treat these conditions can impair weight loss and even promote weight gain.

Continue to: Don't overlook binge-eating disorders

Don’t overlook binge-eating disorders. Screening specifically for binge-eating disorders is important, given the implications on treatment. The US Department of Veterans Affairs developed a single-item tool for this purpose, the VA Binge Eating Screener. The validated questionnaire asks, “On average, how often have you eaten extremely large amounts of food at one time and felt that your eating was out of control at that time?” Response options are: “Never,” “< 1 time/week,” “1 time/week,” “2-4 times/week,” and “5+ times/week.” A response of ≥ 2 times/week had a sensitivity of 88.9% and specificity of 83.2% for binge-eating disorder.³

For patients who prefer a vegan or vegetarian whole food diet, it is important to note that these diets are generally deficient in vitamin B12 and omega 3 fatty acids, so supplementing these should be considered.

Patients with positive screens should undergo psychotherapy and consider pharmacotherapy with lisdexamfetamine as part of their treatment plan. Caution should be used if recommending intermittent fasting for someone with binge-eating disorder.

Evaluate for underlying causes and assess for comorbidities

Review the patient’s current medication list and history. Many medications can cause weight gain, and weight loss can often be achieved by deprescribing such medications. When feasible, prescribe an alternative medication with a more favorable weight profile. A previous article in The Journal of Family Practice addresses this in more depth.⁴

Laboratory and other testing

Laboratory analysis should primarily be focused on determining treatment alterations specific to underlying pathophysiology. Tests to consider ordering are outlined in the Table. Identification of underlying causes and/or comorbid conditions through such testing can guide medication changes, treatment choices, and diet recommendations.

Diabetes and insulin resistance. The American Diabetes Association recommends screening patients who are overweight or obese and have an additional risk factor for diabetes.⁵ This can be done by obtaining a fasting glucose level, hemoglobin A1C, or a 2-hour oral glucose tolerance test.

Continue to: Since it is known that...

Since it is known that insulin resistance increases the risk for coronary heart disease⁶ and can be treated effectively,⁷ we recommend testing for insulin resistance in patients who do not already have impaired fasting glucose, prediabetes, type 2 diabetes, or impaired glucose tolerance. The homeostatic model assessment for insulin resistance (HOMA-IR)⁸ is a measure of insulin resistance and can be calculated from the fasting insulin and fasting glucose levels. This measure should not be done in isolation, but it can be a useful adjunct in identifying patients with insulin resistance and directing treatment.

If there is evidence of diabetes or insulin resistance, consider treatment with metformin ± initiation of a low-carbohydrate diet.

Hypothyroidism. Consider screening for thyroid dysfunction with a thyroid-stimulating hormone level, if it has not been checked previously.

Renal abnormalities. When serum creatinine levels and glomerular filtration rate indicate chronic kidney disease, consider recommending a protein-restricted diet and adjust medications according to renal dosing protocols, as indicated.

Liver abnormalities, including nonalcoholic fatty liver disease (NAFLD). Monitor aspartate aminotransferase and alanine aminotransferase for resolution of elevations as weight loss is achieved. If abnormalities persist, consider ordering a liver ultrasound. Traditionally, low-calorie diets have been prescribed to treat NAFLD, but evidence shows that low-carbohydrate diets can also be effective.⁹

Continue to: Hypertriglyceridemia and low high-density lipoprotein (HDL) levels

Hypertriglyceridemia and low high-density lipoprotein (HDL) levels. Obtain a lipid panel if one has not been completed within the past several years, as hypertriglyceridemia and low HDL can improve dramatically with specific dietary changes.⁷ Observe trends to assess for resolution of lipid abnormalities as weight loss is achieved.

Gout. Consider checking a uric acid level if you are thinking about recommending a low-carbohydrate diet, particularly in patients with a history of gout, as this may temporarily increase the risk of gout flare.

Hypovitaminosis D. If the patient’s vitamin D level is low, consider appropriate supplementation to support the patient’s overall health. While vitamin D deficiency is common in obesity, the role of supplementation in this population is unclear.

Cardiovascular disease. Consider ordering an electrocardiogram, particularly if you are thinking of prescribing medication therapy. Use caution with initiation of certain medications, such as phentermine or diethylproprion, in the presence of arrhythmias or active cardiovascular disease.

Obstructive sleep apnea. Sleep health is important to address, since obesity is one of the most significant risk factors for obstructive sleep apnea.¹⁰ If your patient is given a diagnosis of OSA following a sleep study, consider treatment with continuous positive airway pressure (CPAP), although there are conflicting studies regarding the effects of CPAP therapy in OSA on weight.^11,12

Continue to: Provide guidance on lifestyle changes

Provide guidance on lifestyle changes

Addressing obesity with patients can be challenging in a busy primary care clinic, but it is imperative to helping patients achieve overall health. Counseling on nutrition and physical activity is an important part of this process.

There is no one-size-fits-all approach to nutrition counseling. Focus on creating individualized plans through which patients can achieve success. Some guidance follows, but also beware of common pitfalls that we have observed in clinical practice which, when addressed, can enable significant weight loss (see “Common pitfalls inhibiting weight loss”).

Choose an approach that works for the patient. Commonly prescribed diets to address obesity include, but are not limited to, Atkins, Dietary Approaches to Stop Hypertension (DASH), Glycemic Index, Mediterranean, Ornish, Paleolithic, Zone, whole food plant-based, and ketogenic. We attempt to engage patients in making the decision on what food choices are appropriate for them considering their food availability, culture, and belief systems. For patients who prefer a vegan or vegetarian whole food diet, it is important to note that these diets are generally deficient in vitamin B12 and omega 3 fatty acids, so supplementing these should be considered.

We recommend that patients focus on eliminating sweetened beverages, such as soft drinks, sports drinks, energy drinks, vitamin water, sweet tea, chocolate milk, and Frappuccinos.

Rather than focus on a specific diet, which may not be sustainable long term, encourage healthy eating habits. Low-­carbohydrate diets have been shown to promote greater weight loss compared to low-fat diets.^13,14 Low-calorie diets can also be quite effective in promoting short-term weight loss. In our clinic, when weight loss is the primary goal, patients are typically encouraged to focus on either calorie or carbohydrate restriction in the initial stages of weight loss.

Eliminate sugar and refined carbohydrates. While rigorous mortality data are not available, more recent trials have demonstrated significant improvements in atherosclerotic cardiovascular disease risk markers, including weight reduction and diabetes reversal, when following a diet that markedly decreases carbohydrate intake, especially sugar and refined carbohydrates.^7,14-17

Continue to: We recommend that patients focus...

We recommend that patients focus on eliminating sweetened beverages, such as soft drinks, sports drinks, energy drinks, vitamin water, sweet tea, chocolate milk, and Frappuccinos. We also recommend substantially limiting or eliminating fruit juices and fruit smoothies due to their high sugar content. For example, 8 oz of orange juice contains 26 g of carbohydrates, which is almost as much as 8 oz of soda.

Compared with eating whole fruit, consuming fruit juice has demonstrated a small amount of weight gain in young children and adults.^18,19 It also has shown a higher insulin response compared with eating the same amount of carbohydrates in whole fruit.²⁰ Better options to drink include water, unsweetened tea, and black coffee. Also, avoid ultra-processed carbohydrates from foods such as breads, cereals, and pastries, as they have similar effects on blood glucose when compared to sugar.²¹

Greatly restrict highly processed foods. The evidence suggests that the availability of processed food is associated with increasing obesity.²² Simple advice to offer your patients is to encourage them to shop the perimeter of the grocery store, where fresh produce, meat, and dairy products are primarily located, and avoid the inner aisles, which contain primarily processed foods. Choosing food items with 5 or fewer ingredients is a starting point when teaching patients to read labels.

Consider limiting saturated fats. In 1977, the Dietary Guidelines for Americans recommended that Americans eat no more than 30% of total energy intake from fat and less than 10% of total energy intake from saturated fat; however, no randomized controlled trials had been done that supported this recommendation and epidemiologic data supporting it were weak.²³

The 2015 Dietary Guidelines continue to recommend limiting total energy intake from saturated fats.²⁴ While there may be a small decrease in cardiovascular risk with a reduction of saturated fat intake and replacement with unsaturated fats, no overall mortality benefit has been demonstrated.^24,25 More research is needed in this area to guide patients in decisions regarding consumption of saturated fats and what types of unsaturated fats are best for their health.

Continue to: Eat only 3 meals per day

Eat only 3 meals per day, but aim for fewer than that. The prescription of fasting is a modality that can be used for weight loss and improved health. Fasting has been a prescribed healing practice for thousands of years.²⁶ It is a practice that virtually every major religion in the world embraces. Studies have demonstrated fasting to be safe and effective in the setting of obesity without significant comorbidities, and it may promote weight loss and metabolic health.^26-29

There are multiple types of intermittent fasting. A practical way for patients to start is by restricting the number of hours in which they eat or drink calorie-containing beverages to 8 hours per day. In our experience, this regimen is easier for most patients to follow than alternate-day or other longer fasts. While there has been caution in the prescription of intermittent fasting due to concerns about causing eating disorders, a recent small study did not demonstrate increased risk of eating disorders with daily intermittent fasting.³⁰

Participate in healthy exercise. Nonpharmacologic office-based strategies for treating obesity have generally focused on increasing exercise and decreasing caloric intake.³¹ While exercise has significant health benefits, including preventing weight regain, evidence does not support monotherapy with exercise as an effective long-term weight-loss strategy.³² There are no studies available that adequately support prescribing an exact dose of exercise.³³ Generally, less than 150 minutes of exercise per week is not effective and more than that does have a dose-related response.³³

Follow up to help patients stay on target

There is no ideal interval for follow-up visits. However, frequent visits—anywhere from weekly to monthly—in the initial stages of weight loss increase the patient’s sense of accountability and, in our experience, seem to be helpful.

Patients may also choose to track their progress by weighing themselves regularly. A small study published in the International Journal of Obesity found that patients who weighed themselves daily had greater and more sustained weight loss than those who didn’t.³⁴ But the decision of whether to weigh one’s self at home should be individualized for each patient.

CORRESPONDENCE
Wesley Eichorn, DO, 1000 Oakland Drive, Kalamazoo, MI 49008; [email protected]

In 2015-2016, almost 40% of adults and 18.5% of children ages 2 to 19 years in the United States met the definition for obesity—a chronic, relapsing, multifactorial, neurobehavioral disease that results in adverse metabolic, biomechanical, and psychosocial health consequences.^1,2

Tremendous resources have been invested in research, policy development, and public education to try to prevent obesity and its related complications. Despite this, the obesity epidemic has worsened. Here, we explore how to evaluate and treat obese patients in a primary care setting based on the evidence and our experience seeing patients specifically for weight management in a family medicine residency teaching clinic. Pharmacotherapy and surgery, while often helpful, are outside the scope of this article.

It begins withan obesity-friendly office

Patients may have reservations about health care interactions specific to obesity, so it is important to invite them into a setting that facilitates trust and encourages collaboration. Actively engage patients with unhealthy weight by creating an environment where they feel comfortable. Offer wide chairs without armrests, which will easily accommodate patients of all sizes, and ensure that scales have a weight capacity > 400 lb. Communicate a message to patients, via waiting room materials and videos, that focuses on health rather than on weight or body mass index (BMI).

Understand the patient’s goals and challenges

Most (although not all) family physicians will see obese patients in the context of a visit for diabetes, hypertension, or another condition. However, we feel that having visits specifically to address weight in the initial stages of weight management is helpful. The focus of an initial visit should be getting to know how obesity has affected the patient and what his or her motive is in attempting to lose weight. Explore previous attempts at weight loss and establish what the patient’s highest weight has been, as this will impact weight-loss goals. For example, if a patient has weighed > 300 lb all her adult life, it will be extremely difficult to maintain a weight loss of 150 lb.

What else to ask about. Discuss stressors that may be causing increased food intake or poor food choices, including hunger, anger, loneliness, and sleep difficulties. Multidisciplinary care including a psychologist can aid in addressing these issues. Ask patients if they keep a food diary (and if not, recommend that they start), as food diaries are often helpful in elucidating eating and drinking patterns. Determine a patient’s current and past levels of physical activity, as this will guide the fitness goals you develop for him or her.

Screen for psychosocial disorders

As noted earlier, the physical component of obesity is commonly associated with mood disorders such as anxiety and depression.² This requires a multidisciplinary team effort to facilitate healing in the patient struggling with obesity.

Screening for depression and anxiety using standardized tools such as the Patient Health Questionnaire-9 or the Generalized Anxiety Disorder-7 is encouraged in patients who are overweight or obese. Positive screens should be addressed as part of the patient’s treatment plan, as untreated depression and anxiety can inhibit success with weight loss. Be mindful that many medications commonly used to treat these conditions can impair weight loss and even promote weight gain.

Continue to: Don't overlook binge-eating disorders

Don’t overlook binge-eating disorders. Screening specifically for binge-eating disorders is important, given the implications on treatment. The US Department of Veterans Affairs developed a single-item tool for this purpose, the VA Binge Eating Screener. The validated questionnaire asks, “On average, how often have you eaten extremely large amounts of food at one time and felt that your eating was out of control at that time?” Response options are: “Never,” “< 1 time/week,” “1 time/week,” “2-4 times/week,” and “5+ times/week.” A response of ≥ 2 times/week had a sensitivity of 88.9% and specificity of 83.2% for binge-eating disorder.³

For patients who prefer a vegan or vegetarian whole food diet, it is important to note that these diets are generally deficient in vitamin B12 and omega 3 fatty acids, so supplementing these should be considered.

Patients with positive screens should undergo psychotherapy and consider pharmacotherapy with lisdexamfetamine as part of their treatment plan. Caution should be used if recommending intermittent fasting for someone with binge-eating disorder.

Evaluate for underlying causes and assess for comorbidities

Review the patient’s current medication list and history. Many medications can cause weight gain, and weight loss can often be achieved by deprescribing such medications. When feasible, prescribe an alternative medication with a more favorable weight profile. A previous article in The Journal of Family Practice addresses this in more depth.⁴

Laboratory and other testing

Laboratory analysis should primarily be focused on determining treatment alterations specific to underlying pathophysiology. Tests to consider ordering are outlined in the Table. Identification of underlying causes and/or comorbid conditions through such testing can guide medication changes, treatment choices, and diet recommendations.

Diabetes and insulin resistance. The American Diabetes Association recommends screening patients who are overweight or obese and have an additional risk factor for diabetes.⁵ This can be done by obtaining a fasting glucose level, hemoglobin A1C, or a 2-hour oral glucose tolerance test.

Continue to: Since it is known that...

Since it is known that insulin resistance increases the risk for coronary heart disease⁶ and can be treated effectively,⁷ we recommend testing for insulin resistance in patients who do not already have impaired fasting glucose, prediabetes, type 2 diabetes, or impaired glucose tolerance. The homeostatic model assessment for insulin resistance (HOMA-IR)⁸ is a measure of insulin resistance and can be calculated from the fasting insulin and fasting glucose levels. This measure should not be done in isolation, but it can be a useful adjunct in identifying patients with insulin resistance and directing treatment.

If there is evidence of diabetes or insulin resistance, consider treatment with metformin ± initiation of a low-carbohydrate diet.

Hypothyroidism. Consider screening for thyroid dysfunction with a thyroid-stimulating hormone level, if it has not been checked previously.

Renal abnormalities. When serum creatinine levels and glomerular filtration rate indicate chronic kidney disease, consider recommending a protein-restricted diet and adjust medications according to renal dosing protocols, as indicated.

Liver abnormalities, including nonalcoholic fatty liver disease (NAFLD). Monitor aspartate aminotransferase and alanine aminotransferase for resolution of elevations as weight loss is achieved. If abnormalities persist, consider ordering a liver ultrasound. Traditionally, low-calorie diets have been prescribed to treat NAFLD, but evidence shows that low-carbohydrate diets can also be effective.⁹

Continue to: Hypertriglyceridemia and low high-density lipoprotein (HDL) levels

Hypertriglyceridemia and low high-density lipoprotein (HDL) levels. Obtain a lipid panel if one has not been completed within the past several years, as hypertriglyceridemia and low HDL can improve dramatically with specific dietary changes.⁷ Observe trends to assess for resolution of lipid abnormalities as weight loss is achieved.

Gout. Consider checking a uric acid level if you are thinking about recommending a low-carbohydrate diet, particularly in patients with a history of gout, as this may temporarily increase the risk of gout flare.

Hypovitaminosis D. If the patient’s vitamin D level is low, consider appropriate supplementation to support the patient’s overall health. While vitamin D deficiency is common in obesity, the role of supplementation in this population is unclear.

Cardiovascular disease. Consider ordering an electrocardiogram, particularly if you are thinking of prescribing medication therapy. Use caution with initiation of certain medications, such as phentermine or diethylproprion, in the presence of arrhythmias or active cardiovascular disease.

Obstructive sleep apnea. Sleep health is important to address, since obesity is one of the most significant risk factors for obstructive sleep apnea.¹⁰ If your patient is given a diagnosis of OSA following a sleep study, consider treatment with continuous positive airway pressure (CPAP), although there are conflicting studies regarding the effects of CPAP therapy in OSA on weight.^11,12

Continue to: Provide guidance on lifestyle changes

Provide guidance on lifestyle changes

Addressing obesity with patients can be challenging in a busy primary care clinic, but it is imperative to helping patients achieve overall health. Counseling on nutrition and physical activity is an important part of this process.

There is no one-size-fits-all approach to nutrition counseling. Focus on creating individualized plans through which patients can achieve success. Some guidance follows, but also beware of common pitfalls that we have observed in clinical practice which, when addressed, can enable significant weight loss (see “Common pitfalls inhibiting weight loss”).

Choose an approach that works for the patient. Commonly prescribed diets to address obesity include, but are not limited to, Atkins, Dietary Approaches to Stop Hypertension (DASH), Glycemic Index, Mediterranean, Ornish, Paleolithic, Zone, whole food plant-based, and ketogenic. We attempt to engage patients in making the decision on what food choices are appropriate for them considering their food availability, culture, and belief systems. For patients who prefer a vegan or vegetarian whole food diet, it is important to note that these diets are generally deficient in vitamin B12 and omega 3 fatty acids, so supplementing these should be considered.

We recommend that patients focus on eliminating sweetened beverages, such as soft drinks, sports drinks, energy drinks, vitamin water, sweet tea, chocolate milk, and Frappuccinos.

Rather than focus on a specific diet, which may not be sustainable long term, encourage healthy eating habits. Low-­carbohydrate diets have been shown to promote greater weight loss compared to low-fat diets.^13,14 Low-calorie diets can also be quite effective in promoting short-term weight loss. In our clinic, when weight loss is the primary goal, patients are typically encouraged to focus on either calorie or carbohydrate restriction in the initial stages of weight loss.

Eliminate sugar and refined carbohydrates. While rigorous mortality data are not available, more recent trials have demonstrated significant improvements in atherosclerotic cardiovascular disease risk markers, including weight reduction and diabetes reversal, when following a diet that markedly decreases carbohydrate intake, especially sugar and refined carbohydrates.^7,14-17

Continue to: We recommend that patients focus...

We recommend that patients focus on eliminating sweetened beverages, such as soft drinks, sports drinks, energy drinks, vitamin water, sweet tea, chocolate milk, and Frappuccinos. We also recommend substantially limiting or eliminating fruit juices and fruit smoothies due to their high sugar content. For example, 8 oz of orange juice contains 26 g of carbohydrates, which is almost as much as 8 oz of soda.

Compared with eating whole fruit, consuming fruit juice has demonstrated a small amount of weight gain in young children and adults.^18,19 It also has shown a higher insulin response compared with eating the same amount of carbohydrates in whole fruit.²⁰ Better options to drink include water, unsweetened tea, and black coffee. Also, avoid ultra-processed carbohydrates from foods such as breads, cereals, and pastries, as they have similar effects on blood glucose when compared to sugar.²¹

Greatly restrict highly processed foods. The evidence suggests that the availability of processed food is associated with increasing obesity.²² Simple advice to offer your patients is to encourage them to shop the perimeter of the grocery store, where fresh produce, meat, and dairy products are primarily located, and avoid the inner aisles, which contain primarily processed foods. Choosing food items with 5 or fewer ingredients is a starting point when teaching patients to read labels.

Consider limiting saturated fats. In 1977, the Dietary Guidelines for Americans recommended that Americans eat no more than 30% of total energy intake from fat and less than 10% of total energy intake from saturated fat; however, no randomized controlled trials had been done that supported this recommendation and epidemiologic data supporting it were weak.²³

The 2015 Dietary Guidelines continue to recommend limiting total energy intake from saturated fats.²⁴ While there may be a small decrease in cardiovascular risk with a reduction of saturated fat intake and replacement with unsaturated fats, no overall mortality benefit has been demonstrated.^24,25 More research is needed in this area to guide patients in decisions regarding consumption of saturated fats and what types of unsaturated fats are best for their health.

Continue to: Eat only 3 meals per day

Eat only 3 meals per day, but aim for fewer than that. The prescription of fasting is a modality that can be used for weight loss and improved health. Fasting has been a prescribed healing practice for thousands of years.²⁶ It is a practice that virtually every major religion in the world embraces. Studies have demonstrated fasting to be safe and effective in the setting of obesity without significant comorbidities, and it may promote weight loss and metabolic health.^26-29

There are multiple types of intermittent fasting. A practical way for patients to start is by restricting the number of hours in which they eat or drink calorie-containing beverages to 8 hours per day. In our experience, this regimen is easier for most patients to follow than alternate-day or other longer fasts. While there has been caution in the prescription of intermittent fasting due to concerns about causing eating disorders, a recent small study did not demonstrate increased risk of eating disorders with daily intermittent fasting.³⁰

Participate in healthy exercise. Nonpharmacologic office-based strategies for treating obesity have generally focused on increasing exercise and decreasing caloric intake.³¹ While exercise has significant health benefits, including preventing weight regain, evidence does not support monotherapy with exercise as an effective long-term weight-loss strategy.³² There are no studies available that adequately support prescribing an exact dose of exercise.³³ Generally, less than 150 minutes of exercise per week is not effective and more than that does have a dose-related response.³³

Follow up to help patients stay on target

There is no ideal interval for follow-up visits. However, frequent visits—anywhere from weekly to monthly—in the initial stages of weight loss increase the patient’s sense of accountability and, in our experience, seem to be helpful.

Patients may also choose to track their progress by weighing themselves regularly. A small study published in the International Journal of Obesity found that patients who weighed themselves daily had greater and more sustained weight loss than those who didn’t.³⁴ But the decision of whether to weigh one’s self at home should be individualized for each patient.

CORRESPONDENCE
Wesley Eichorn, DO, 1000 Oakland Drive, Kalamazoo, MI 49008; [email protected]

In 2015-2016, almost 40% of adults and 18.5% of children ages 2 to 19 years in the United States met the definition for obesity—a chronic, relapsing, multifactorial, neurobehavioral disease that results in adverse metabolic, biomechanical, and psychosocial health consequences.^1,2

Tremendous resources have been invested in research, policy development, and public education to try to prevent obesity and its related complications. Despite this, the obesity epidemic has worsened. Here, we explore how to evaluate and treat obese patients in a primary care setting based on the evidence and our experience seeing patients specifically for weight management in a family medicine residency teaching clinic. Pharmacotherapy and surgery, while often helpful, are outside the scope of this article.

It begins withan obesity-friendly office

Patients may have reservations about health care interactions specific to obesity, so it is important to invite them into a setting that facilitates trust and encourages collaboration. Actively engage patients with unhealthy weight by creating an environment where they feel comfortable. Offer wide chairs without armrests, which will easily accommodate patients of all sizes, and ensure that scales have a weight capacity > 400 lb. Communicate a message to patients, via waiting room materials and videos, that focuses on health rather than on weight or body mass index (BMI).

Understand the patient’s goals and challenges

Most (although not all) family physicians will see obese patients in the context of a visit for diabetes, hypertension, or another condition. However, we feel that having visits specifically to address weight in the initial stages of weight management is helpful. The focus of an initial visit should be getting to know how obesity has affected the patient and what his or her motive is in attempting to lose weight. Explore previous attempts at weight loss and establish what the patient’s highest weight has been, as this will impact weight-loss goals. For example, if a patient has weighed > 300 lb all her adult life, it will be extremely difficult to maintain a weight loss of 150 lb.

What else to ask about. Discuss stressors that may be causing increased food intake or poor food choices, including hunger, anger, loneliness, and sleep difficulties. Multidisciplinary care including a psychologist can aid in addressing these issues. Ask patients if they keep a food diary (and if not, recommend that they start), as food diaries are often helpful in elucidating eating and drinking patterns. Determine a patient’s current and past levels of physical activity, as this will guide the fitness goals you develop for him or her.

Screen for psychosocial disorders

As noted earlier, the physical component of obesity is commonly associated with mood disorders such as anxiety and depression.² This requires a multidisciplinary team effort to facilitate healing in the patient struggling with obesity.

Screening for depression and anxiety using standardized tools such as the Patient Health Questionnaire-9 or the Generalized Anxiety Disorder-7 is encouraged in patients who are overweight or obese. Positive screens should be addressed as part of the patient’s treatment plan, as untreated depression and anxiety can inhibit success with weight loss. Be mindful that many medications commonly used to treat these conditions can impair weight loss and even promote weight gain.

Continue to: Don't overlook binge-eating disorders

Don’t overlook binge-eating disorders. Screening specifically for binge-eating disorders is important, given the implications on treatment. The US Department of Veterans Affairs developed a single-item tool for this purpose, the VA Binge Eating Screener. The validated questionnaire asks, “On average, how often have you eaten extremely large amounts of food at one time and felt that your eating was out of control at that time?” Response options are: “Never,” “< 1 time/week,” “1 time/week,” “2-4 times/week,” and “5+ times/week.” A response of ≥ 2 times/week had a sensitivity of 88.9% and specificity of 83.2% for binge-eating disorder.³

For patients who prefer a vegan or vegetarian whole food diet, it is important to note that these diets are generally deficient in vitamin B12 and omega 3 fatty acids, so supplementing these should be considered.

Patients with positive screens should undergo psychotherapy and consider pharmacotherapy with lisdexamfetamine as part of their treatment plan. Caution should be used if recommending intermittent fasting for someone with binge-eating disorder.

Evaluate for underlying causes and assess for comorbidities

Review the patient’s current medication list and history. Many medications can cause weight gain, and weight loss can often be achieved by deprescribing such medications. When feasible, prescribe an alternative medication with a more favorable weight profile. A previous article in The Journal of Family Practice addresses this in more depth.⁴

Laboratory and other testing

Laboratory analysis should primarily be focused on determining treatment alterations specific to underlying pathophysiology. Tests to consider ordering are outlined in the Table. Identification of underlying causes and/or comorbid conditions through such testing can guide medication changes, treatment choices, and diet recommendations.

Diabetes and insulin resistance. The American Diabetes Association recommends screening patients who are overweight or obese and have an additional risk factor for diabetes.⁵ This can be done by obtaining a fasting glucose level, hemoglobin A1C, or a 2-hour oral glucose tolerance test.

Continue to: Since it is known that...

Since it is known that insulin resistance increases the risk for coronary heart disease⁶ and can be treated effectively,⁷ we recommend testing for insulin resistance in patients who do not already have impaired fasting glucose, prediabetes, type 2 diabetes, or impaired glucose tolerance. The homeostatic model assessment for insulin resistance (HOMA-IR)⁸ is a measure of insulin resistance and can be calculated from the fasting insulin and fasting glucose levels. This measure should not be done in isolation, but it can be a useful adjunct in identifying patients with insulin resistance and directing treatment.

If there is evidence of diabetes or insulin resistance, consider treatment with metformin ± initiation of a low-carbohydrate diet.

Hypothyroidism. Consider screening for thyroid dysfunction with a thyroid-stimulating hormone level, if it has not been checked previously.

Renal abnormalities. When serum creatinine levels and glomerular filtration rate indicate chronic kidney disease, consider recommending a protein-restricted diet and adjust medications according to renal dosing protocols, as indicated.

Liver abnormalities, including nonalcoholic fatty liver disease (NAFLD). Monitor aspartate aminotransferase and alanine aminotransferase for resolution of elevations as weight loss is achieved. If abnormalities persist, consider ordering a liver ultrasound. Traditionally, low-calorie diets have been prescribed to treat NAFLD, but evidence shows that low-carbohydrate diets can also be effective.⁹

Continue to: Hypertriglyceridemia and low high-density lipoprotein (HDL) levels

Hypertriglyceridemia and low high-density lipoprotein (HDL) levels. Obtain a lipid panel if one has not been completed within the past several years, as hypertriglyceridemia and low HDL can improve dramatically with specific dietary changes.⁷ Observe trends to assess for resolution of lipid abnormalities as weight loss is achieved.

Gout. Consider checking a uric acid level if you are thinking about recommending a low-carbohydrate diet, particularly in patients with a history of gout, as this may temporarily increase the risk of gout flare.

Hypovitaminosis D. If the patient’s vitamin D level is low, consider appropriate supplementation to support the patient’s overall health. While vitamin D deficiency is common in obesity, the role of supplementation in this population is unclear.

Cardiovascular disease. Consider ordering an electrocardiogram, particularly if you are thinking of prescribing medication therapy. Use caution with initiation of certain medications, such as phentermine or diethylproprion, in the presence of arrhythmias or active cardiovascular disease.

Obstructive sleep apnea. Sleep health is important to address, since obesity is one of the most significant risk factors for obstructive sleep apnea.¹⁰ If your patient is given a diagnosis of OSA following a sleep study, consider treatment with continuous positive airway pressure (CPAP), although there are conflicting studies regarding the effects of CPAP therapy in OSA on weight.^11,12

Continue to: Provide guidance on lifestyle changes

Provide guidance on lifestyle changes

Addressing obesity with patients can be challenging in a busy primary care clinic, but it is imperative to helping patients achieve overall health. Counseling on nutrition and physical activity is an important part of this process.

There is no one-size-fits-all approach to nutrition counseling. Focus on creating individualized plans through which patients can achieve success. Some guidance follows, but also beware of common pitfalls that we have observed in clinical practice which, when addressed, can enable significant weight loss (see “Common pitfalls inhibiting weight loss”).

Choose an approach that works for the patient. Commonly prescribed diets to address obesity include, but are not limited to, Atkins, Dietary Approaches to Stop Hypertension (DASH), Glycemic Index, Mediterranean, Ornish, Paleolithic, Zone, whole food plant-based, and ketogenic. We attempt to engage patients in making the decision on what food choices are appropriate for them considering their food availability, culture, and belief systems. For patients who prefer a vegan or vegetarian whole food diet, it is important to note that these diets are generally deficient in vitamin B12 and omega 3 fatty acids, so supplementing these should be considered.

We recommend that patients focus on eliminating sweetened beverages, such as soft drinks, sports drinks, energy drinks, vitamin water, sweet tea, chocolate milk, and Frappuccinos.

Rather than focus on a specific diet, which may not be sustainable long term, encourage healthy eating habits. Low-­carbohydrate diets have been shown to promote greater weight loss compared to low-fat diets.^13,14 Low-calorie diets can also be quite effective in promoting short-term weight loss. In our clinic, when weight loss is the primary goal, patients are typically encouraged to focus on either calorie or carbohydrate restriction in the initial stages of weight loss.

Eliminate sugar and refined carbohydrates. While rigorous mortality data are not available, more recent trials have demonstrated significant improvements in atherosclerotic cardiovascular disease risk markers, including weight reduction and diabetes reversal, when following a diet that markedly decreases carbohydrate intake, especially sugar and refined carbohydrates.^7,14-17

Continue to: We recommend that patients focus...

We recommend that patients focus on eliminating sweetened beverages, such as soft drinks, sports drinks, energy drinks, vitamin water, sweet tea, chocolate milk, and Frappuccinos. We also recommend substantially limiting or eliminating fruit juices and fruit smoothies due to their high sugar content. For example, 8 oz of orange juice contains 26 g of carbohydrates, which is almost as much as 8 oz of soda.

Compared with eating whole fruit, consuming fruit juice has demonstrated a small amount of weight gain in young children and adults.^18,19 It also has shown a higher insulin response compared with eating the same amount of carbohydrates in whole fruit.²⁰ Better options to drink include water, unsweetened tea, and black coffee. Also, avoid ultra-processed carbohydrates from foods such as breads, cereals, and pastries, as they have similar effects on blood glucose when compared to sugar.²¹

Greatly restrict highly processed foods. The evidence suggests that the availability of processed food is associated with increasing obesity.²² Simple advice to offer your patients is to encourage them to shop the perimeter of the grocery store, where fresh produce, meat, and dairy products are primarily located, and avoid the inner aisles, which contain primarily processed foods. Choosing food items with 5 or fewer ingredients is a starting point when teaching patients to read labels.

Consider limiting saturated fats. In 1977, the Dietary Guidelines for Americans recommended that Americans eat no more than 30% of total energy intake from fat and less than 10% of total energy intake from saturated fat; however, no randomized controlled trials had been done that supported this recommendation and epidemiologic data supporting it were weak.²³

The 2015 Dietary Guidelines continue to recommend limiting total energy intake from saturated fats.²⁴ While there may be a small decrease in cardiovascular risk with a reduction of saturated fat intake and replacement with unsaturated fats, no overall mortality benefit has been demonstrated.^24,25 More research is needed in this area to guide patients in decisions regarding consumption of saturated fats and what types of unsaturated fats are best for their health.

Continue to: Eat only 3 meals per day

Eat only 3 meals per day, but aim for fewer than that. The prescription of fasting is a modality that can be used for weight loss and improved health. Fasting has been a prescribed healing practice for thousands of years.²⁶ It is a practice that virtually every major religion in the world embraces. Studies have demonstrated fasting to be safe and effective in the setting of obesity without significant comorbidities, and it may promote weight loss and metabolic health.^26-29

There are multiple types of intermittent fasting. A practical way for patients to start is by restricting the number of hours in which they eat or drink calorie-containing beverages to 8 hours per day. In our experience, this regimen is easier for most patients to follow than alternate-day or other longer fasts. While there has been caution in the prescription of intermittent fasting due to concerns about causing eating disorders, a recent small study did not demonstrate increased risk of eating disorders with daily intermittent fasting.³⁰

Participate in healthy exercise. Nonpharmacologic office-based strategies for treating obesity have generally focused on increasing exercise and decreasing caloric intake.³¹ While exercise has significant health benefits, including preventing weight regain, evidence does not support monotherapy with exercise as an effective long-term weight-loss strategy.³² There are no studies available that adequately support prescribing an exact dose of exercise.³³ Generally, less than 150 minutes of exercise per week is not effective and more than that does have a dose-related response.³³

Follow up to help patients stay on target

There is no ideal interval for follow-up visits. However, frequent visits—anywhere from weekly to monthly—in the initial stages of weight loss increase the patient’s sense of accountability and, in our experience, seem to be helpful.

Patients may also choose to track their progress by weighing themselves regularly. A small study published in the International Journal of Obesity found that patients who weighed themselves daily had greater and more sustained weight loss than those who didn’t.³⁴ But the decision of whether to weigh one’s self at home should be individualized for each patient.

CORRESPONDENCE
Wesley Eichorn, DO, 1000 Oakland Drive, Kalamazoo, MI 49008; [email protected]

The incidence of posttransplant malignancy among solid organ transplant recipients (SOTRs) is 10%; skin cancer, primarily nonmelanoma skin cancer (NMSC), constitutes 49.5% of all malignancies in this population.¹ The etiology of the increased risk of cutaneous malignancy in SOTR is multifactorial:

• The skin of SOTRs is photosensitive, compared to that of immunocompetent patients, thus predisposing SOTRs to carcinogenic damage resulting from exposure to UV light.²
• Immunosuppression plays a key role in increasing the risk of cutaneous malignancy by inhibiting the ability of the immune system to recognize and destroy tumor cells.³
• Human papillomavirus (HPV) can play a role in carcinogenesis by promoting molecular pathways to proliferation and survival of nascent tumor cells⁴;Times New Romanβ-HPV strains are disseminated ubiquitously in the skin of immunosuppressed patients.⁵
• Some medications administered after transplantation can be directly carcinogenic.

NMSC in SOTRs also differs qualitatively from NMSC in immunocompetent patients. Cutaneous squamous cell carcinoma (cSCC) (FIGUREs 1 and 2) is the most common skin cancer among SOTRs, whereas basal cell carcinoma (BCC) is the most common skin cancer in the general population.³ cSCC in the SOTR population tends to be more aggressive, with more rapid local invasion and an increased rate of both in-transit and distant metastases, leading to an increase in morbidity and mortality. Mortality of metastatic cSCC among SOTRs is approximately 50%, compared to 20% in an otherwise healthy population.^3,6-8

The problem is relevant to primary care

Screening. Because there is a demonstrated reduction in morbidity and mortality associated with early detection and treatment of NMSC, regular screening of skin is important in the SOTR population.⁹ A study in Ontario, Canada, from 1994 to 2012 and comprising 10,183 SOTRs, found that adherence to an annual skin check regimen for ≥ 75% of the observation period was associated with a 34% reduction in cutaneous BCC- and cSCC-­related morbidity or death (adjusted hazard ratio = 0.66; 95% CI, 0.48-0.92).¹⁰ Although routine follow-up with a dermatologist is recommended for SOTRs,^9,11-15 only 2.1% of patients in the Canadian study were fully adherent with annual skin examination, and 55% never visited a dermatologist.¹⁰ Consequently, primary care physicians can play a key role in skin cancer screening for SOTRs.

Education regarding the importance of protection from the sun is also an essential part of primary care. A 2018 study of SOTRs in Turkey demonstrated that¹⁶

• 46% expressed a lack of knowledge of the hazards of sun exposure
• 44% did not recall ever receiving medical advice regarding sun protection
• 89% did not wear sun-protective clothing
• 86% did not use sunscreen daily.

Multiple studies have demonstrated the positive effect that preventive education and attendance at a dermatology or skin cancer screening clinic can have on sun-protective behaviors among SOTRs.^9,16-18 In the Turkish study, 100% of patients who reported using sunscreen daily had been undergoing regular dermatologic examination.¹⁶

In this article, we review current management guidelines regarding the prevention and treatment of NMSC in SOTRs.

Recommendations for prevention

Screening skin exams (TABLE 1^{1,11,12,15,19-23}). Although definitive guidelines do not exist regarding the frequency of a screening skin exam for SOTRs, multiple frequency-­determining algorithms have been proposed.^11,12,15,19 The recommended frequency of a skin exam is based on history of skin cancer; for SOTRs, the most common recommendation¹⁹ is a full-body skin examination as follows:

• annually—when there is no history of skin cancer
• every 6 months—when there is a history of actinic keratoses (AKs; precancerous lesions that carry a risk of transforming into cSCC) or a single low-risk NMSC
• every 3 months—when there is a history of multiple NMSCs or a single high-risk NMSC
• every 1 to 3 months—when there is a history of metastatic disease.

Continue to: Other risk factors...

Other risk factors for NMSC to consider in SOTRs when determining an appropriate follow-up regimen include any of the following^{1,20,21,24-26}:

• male gender, fair skin, history of childhood sunburn, history of smoking
• lung or heart transplantation, history of episodes of transplant rejection, age ≥ 50 years at transplantation
• immunosuppression with calcineurin inhibitors, compared to mammalian target of rapamycin (mTOR) inhibitors
• immunosuppression with cyclosporine, compared to tacrolimus
• an immunosuppressive regimen with > 1 immunosuppressant or an increased degree of immunosuppression
• antithymocyte globulin within the first year posttransplantation.

Regular screening of skin is important in the solid organ transplant population.

Because the intensity of immunosuppression and individual immunosuppressants used affect the risk of NMSC, conduct a thorough medication review with SOTRs at all visits. Ask about new, changing, or symptomatic (pruritic, painful, bleeding) skin lesions, and perform a full-body skin exam. Palpate draining lymph nodes if the patient has a history of NMSC.¹⁵ AKs (FIGURE 3) should be treated aggressively with liquid nitrogen or field therapy. Lesions suspicious for NMSC should be biopsied and sent for histologic evaluation.²² Shave, punch, and excisional biopsies are all adequate techniques; however, because all cSCCs in SOTRs are considered high risk for aggressive features, biopsy should extend at least into the reticular dermis to allow evaluation for invasive disease.²²

Sun-protective measures (TABLE 1^{1,11,12,15,19-23}). Inquire about patients’ habits related to protection from the sun, their knowledge of recommended sun-protective measures, and risks associated with nonadherence. Recommended sun-protective measures include

• daily broad-spectrum sunscreen (SPF ≥ 30), reapplied every 2 hours of sun exposure, in accordance with labeling instructions²³
• sun-protective clothing (pants, long sleeves, hat, sunglasses)²³
• avoidance of tanning salons.¹⁵

SOTRs who adequately adhere to sun-protective measures might need vitamin D supplementation because sunscreen and sun-protective clothing inhibit cutaneous synthesis of vitamin D.¹⁵

Recommendations for treatment

Consider chemoprophylactic therapy for SOTRs who have had multiple prior cutaneous malignancies or multiple AKs.

Continue to: Topical chemoprophylaxis

Topical medications used for cSCC chemoprophylaxis include 5-fluorouracil (5-FU), photodynamic therapy (PDT), imiquimod, ingenol mebutate, topical retinoids, and diclofenac.²⁷ (See TABLE 2.^27-40) Of these, the latter 3 are used less commonly because of the small packaging size of ingenol mebutate and the relative lack of efficacy data for topical retinoids and diclofenac.²⁷ Imiquimod is often avoided when treating large surface areas because of the risk of systemic adverse effects associated with cytokine release.²⁷

5-FU is US Food and Drug Administration (FDA)-approved for the treatment of AKs, and is used off-label for treating cSCC in situ (Bowen disease). It is the most commonly used topical therapy for field disease.^27-29 5-FU is typically applied once or twice daily for 3 to 4 weeks. Common adverse effects include transient skin irritation and erythema.²⁷

PDT involves topical application of a photosensitizer, such as 5-aminolevulinic acid or methyl aminolevulinate, followed by exposure to a visible light source, leading to antitumor effects on gene expression and destruction of proliferating cells through production of reactive oxygen species.^30,31 Evidence is sufficient to support routine use of PDT for AKs and Bowen disease.³⁰ A mild sunburn-like reaction is common following PDT, with transient erythema and discomfort typically lasting 1 to 2 weeks but not typically necessitating analgesic therapy.²⁷

Imiquimod is a ligand that binds to and activates Toll-like receptor 7, leading to enhancement of the cell-mediated antitumor immune response and resultant tissue-­specific apoptosis coordinated by type 1 T-helper lymphocytes.³² Topical imiquimod cream is FDA approved for field treatment of AKs at 2.5%, 3.75%, and 5% concentrations; efficacy has been demonstrated in the SOTR population.^33,41 Multiple studies in immunocompetent patients have suggested that imiquimod might be slightly less efficacious than 5-FU.^42-44

The tolerability of field treatment with imiquimod has been called into question.²⁷ However, in a 2019 study comparing adverse reactions among 513 immunocompetent patients with field disease who were treated with either 5-FU 5% cream; imiquimod 5% cream; PDT with methyl aminolevulinate; or ingenol mebutate 0.015% gel, a similar or smaller percentage of patients treated with imiquimod reported moderate-to-severe itching, moderate-to-severe pain, and any adverse events, compared to patients treated with the other options.⁴⁴

Continue to: Diclofenac

Diclofenac is a nonsteroidal anti-­inflammatory drug that reversibly inhibits the enzymes cyclooxygenase-1 and ­cyclooxygenase-2, resulting in a decrease in the formation of inflammatory prostaglandins, which have been observed in chronically sun-damaged skin, AKs, and cSCC.^34,45 Diclofenac 3% gel, applied topically twice daily for 60 to 90 days has been approved by the FDA for treatment of AKs, in conjunction with sun avoidance.³⁴ Topical diclofenac has been demonstrated to be efficacious in treating AKs in the SOTR population^46,47; however, multiple meta-analyses using data from immunocompetent patients have demonstrated that topical diclofenac is inferior to other treatment options, particularly 5-FU, at achieving complete clearance of AKs.^43,48,49 Diclofenac might be a useful option when patient adherence is expected to be difficult because of adverse effects of therapy: Multiple studies have suggested that diclofenac might be more tolerable than other options.^43,48,50

Systemic chemoprophylaxis

Systemic therapies that have been used for chemoprophylaxis against cutaneous malignancy include nicotinamide, oral retinoids, capecitabine, and HPV vaccination. (See TABLE 2.^27-40)

Nicotinamide, the amide form of vitamin B₃, protects against cutaneous malignancy by aiding repair of DNA damaged by ionizing radiation, such as UV light.²⁷ Efficacy has been demonstrated in reducing development of new AKs and cSCC in immunocompetent patients with a history of more than 2 keratinocyte carcinomas within a 5-year span.^27,35 Nicotinamide is especially relevant to the SOTR population because it reduces the level of cutaneous immunity suppression induced by UV radiation without altering patients’ baseline immunity.^27,36

Because the intensity of immunosuppression and the individual immunosuppressants used affect the risk of nonmelanoma skin cancer, conduct a thorough medication review at all visits.

There are insufficient long-term follow-up data in the literature to assess the sustainability of the antitumor effects of nicotinamide; studies specific to the SOTR population have been underpowered for assessing its impact on formation of cSCC.^27,35Patients taking nicotinamide should be informed of the risk of liver failure at dosages > 3 g/d (antitumor efficacy has been demonstrated at 500 mg twice daily) and advised to avoid purchasing over-the-counter nicotinic acid or niacin as a substitute for nicotinamide, because of the increased incidence of flushing associated with their use.²⁷

Oral retinoids. Systemic retinoids—in particular, acitretin—are efficacious in reducing the risk of cSCC in SOTRs.^27,37,38 The primary drawback to cSCC prophylaxis with oral retinoids is a rebound effect, in which treatment discontinuation leads to a rapid return to baseline cSCC formation.²⁷

Continue to: Pregnancy must be avoided...

Pregnancy must be avoided while taking an oral retinoid. Because acitretin can persist in the body for years after discontinuation, its use should generally be avoided in patients of childbearing potential. An FDA black box warning states that patients of childbearing potential must be counseled to use 2 forms of birth control to avoid pregnancy for ≥ 3 years after cessation of oral acitretin. Prior to initiation of oral retinoid therapy, the following baseline laboratory tests should be obtained: complete blood count, creatinine, lipid panel, and liver function tests. For patients with a history of chronic kidney disease or renal transplantation, the lipid panel, liver function tests, and creatinine assay should be repeated with each dosage adjustment and every 3 months once goal-dosing is achieved.²⁷

Capecitabine is typically initiated with the help of Medical Oncology.^27,40 A prodrug metabolized by dihydropyrimidine dehydrogenase to 5-FU, capecitabine interacts with warfarin, leading to a significant increase in prothrombin time.³⁹ Other adverse effects associated with oral capecitabine include fatigue, palmar-plantar erythrodysesthesia, diarrhea, and, rarely, neutropenia. Although dihydropyrimidine dehydrogenase deficiency is rare, treatment with capecitabine in patients who have this enzyme deficiency might lead to severe toxicity or death.²⁷

HPV vaccination. HPV might play a role in the development of cutaneous malignancy, especially in immunosuppressed patients.^4,5 The utility of HPV vaccination in the prevention of NMSC has yet to be determined, but vaccination has been shown, in case reports, to be helpful in immunocompetent patients.^51,52 The immunogenicity of HPV vaccination in the SOTR population is uncertain, and the most common HPV types found in SOTRs are not specifically covered by available HPV vaccines.¹⁹

The role of immunosuppression reduction and immunosuppressive replacement

Both the degree of immunosuppression and the individual agents used can affect a patient’s risk of NMSC. Immunosuppression reduction should be considered if skin cancer poses a major risk to the patient’s health and if that risk outweighs the risk of graft rejection associated with immunosuppression reduction.²⁷ In a cohort of 180 kidney and liver SOTRs who developed de novo carcinoma (excluding NMSC) after transplantation, neither reduction of immunosuppression nor introduction of an mTOR inhibitor affected graft survival or oncologic treatment tolerance.⁵³ Because mTOR inhibitors have a protective effect against development of NMSC, they are the preferred choice of immunosuppressive agent from a dermatologic perspective.^1,27,54-57 Decisions regarding changes in immunosuppression are generally made by, or in collaboration with, the patient’s transplant physician.

Recommendations: Treating cSCC

Risk should guide strategy

Consider chemoprophylactic therapy for solid organ transplant recipients who have had multiple prior cutaneous malignancies or multiple AKs.

Small lesions of the trunk and extremities without high-risk features can be treated with a destructive method (eg, electrodessication and curettage). However, lesions of the head and neck and those found to have features consistent with an increased risk of recurrence or metastasis should be treated aggressively.^3,58,59

Continue to: Risk factors for invasive growth...

Risk factors for invasive growth, recurrence, or metastasis of cSCC in SOTRs are multiple lesions or satellite lesions, indistinct clinical borders, rapid growth, ulceration, and recurrence after treatment.⁶⁰ The risk of invasive growth, recurrence, and metastasis of cSCC also increases with size and location of the lesion, according to this framework⁶⁰:

• any size in scar tissue, areas of chronic inflammation, and fields of prior radiation therapy
• ≥ 0.6 cm on hands, feet, genitalia, and mask areas of the face (central face, eyelids, eyebrows, nose, lips, chin, mandible, and temporal, preauricular, postauricular, and periorbital areas)
• > 1 cm on cheeks, forehead, neck, and scalp
• > 2 cm on the trunk and extremities.

In addition, specific findings on histologic analysis portend increased risk of invasive growth, recurrence, or metastasis:

• poor differentiation
• deep extension of the tumor into subcutaneous fat
• perineural invasion or inflammation
• perivascular or intravascular invasion.

Treatment modalities

Mohs surgery is preferred to ensure margin clearance while preserving noninvolved tissue^3,7 (FIGURE 4). If Mohs surgery is not possible, the lesion should be excised with 3- to 10-mm margins.^3,60 Based on current literature, the roles of nodal staging, sentinel lymph node biopsy, and adjuvant therapy are not well defined, but it is likely that these interventions will play a pivotal role in the management of advanced cSCC in SOTRs in the future.³

Pregnancy must be avoided while taking an oral retinoid; because of its persistence, acitretin should generally be avoided in patients of childbearing potential.

Nonsurgical therapeutic options for primary or adjuvant treatment of cSCC include systemic chemotherapy, radiotherapy, and programmed cell death protein 1 inhibitors. (For more on treatment modalities, see TABLE 3.^3,7,58-61)

Recommendations: Treating BCC

BCC in SOTRs is treated similarly (TABLE 3^3,7,58-61) to how it is treated in the immunocompetent population—except that SOTRs require closer follow-up than nontransplant patients because they are at higher risk of recurrence and new NMSCs.³ Standard management after biopsy is either^3,61:

• Mohs surgery to ensure margin control (for most BCCs on the head and neck and those with clinical or histologic risk factors for recurrence or aggressive behavior)
• excision with a 4- or 5-mm margin or a destructive modality (for BCCs on the trunk and extremities without risk factors for recurrence).

Radiotherapy is an alternative for patients with high-risk BCCs who are unable to tolerate surgery.³

CORRESPONDENCE
Lindsey Collins, MD, Department of Dermatology, University of Oklahoma Health Sciences Center, 619 NE 13th Steet, Oklahoma City, OK 73104; [email protected]

The incidence of posttransplant malignancy among solid organ transplant recipients (SOTRs) is 10%; skin cancer, primarily nonmelanoma skin cancer (NMSC), constitutes 49.5% of all malignancies in this population.¹ The etiology of the increased risk of cutaneous malignancy in SOTR is multifactorial:

• The skin of SOTRs is photosensitive, compared to that of immunocompetent patients, thus predisposing SOTRs to carcinogenic damage resulting from exposure to UV light.²
• Immunosuppression plays a key role in increasing the risk of cutaneous malignancy by inhibiting the ability of the immune system to recognize and destroy tumor cells.³
• Human papillomavirus (HPV) can play a role in carcinogenesis by promoting molecular pathways to proliferation and survival of nascent tumor cells⁴;Times New Romanβ-HPV strains are disseminated ubiquitously in the skin of immunosuppressed patients.⁵
• Some medications administered after transplantation can be directly carcinogenic.

NMSC in SOTRs also differs qualitatively from NMSC in immunocompetent patients. Cutaneous squamous cell carcinoma (cSCC) (FIGUREs 1 and 2) is the most common skin cancer among SOTRs, whereas basal cell carcinoma (BCC) is the most common skin cancer in the general population.³ cSCC in the SOTR population tends to be more aggressive, with more rapid local invasion and an increased rate of both in-transit and distant metastases, leading to an increase in morbidity and mortality. Mortality of metastatic cSCC among SOTRs is approximately 50%, compared to 20% in an otherwise healthy population.^3,6-8

The problem is relevant to primary care

Screening. Because there is a demonstrated reduction in morbidity and mortality associated with early detection and treatment of NMSC, regular screening of skin is important in the SOTR population.⁹ A study in Ontario, Canada, from 1994 to 2012 and comprising 10,183 SOTRs, found that adherence to an annual skin check regimen for ≥ 75% of the observation period was associated with a 34% reduction in cutaneous BCC- and cSCC-­related morbidity or death (adjusted hazard ratio = 0.66; 95% CI, 0.48-0.92).¹⁰ Although routine follow-up with a dermatologist is recommended for SOTRs,^9,11-15 only 2.1% of patients in the Canadian study were fully adherent with annual skin examination, and 55% never visited a dermatologist.¹⁰ Consequently, primary care physicians can play a key role in skin cancer screening for SOTRs.

Education regarding the importance of protection from the sun is also an essential part of primary care. A 2018 study of SOTRs in Turkey demonstrated that¹⁶

• 46% expressed a lack of knowledge of the hazards of sun exposure
• 44% did not recall ever receiving medical advice regarding sun protection
• 89% did not wear sun-protective clothing
• 86% did not use sunscreen daily.

Multiple studies have demonstrated the positive effect that preventive education and attendance at a dermatology or skin cancer screening clinic can have on sun-protective behaviors among SOTRs.^9,16-18 In the Turkish study, 100% of patients who reported using sunscreen daily had been undergoing regular dermatologic examination.¹⁶

In this article, we review current management guidelines regarding the prevention and treatment of NMSC in SOTRs.

Recommendations for prevention

Screening skin exams (TABLE 1^{1,11,12,15,19-23}). Although definitive guidelines do not exist regarding the frequency of a screening skin exam for SOTRs, multiple frequency-­determining algorithms have been proposed.^11,12,15,19 The recommended frequency of a skin exam is based on history of skin cancer; for SOTRs, the most common recommendation¹⁹ is a full-body skin examination as follows:

• annually—when there is no history of skin cancer
• every 6 months—when there is a history of actinic keratoses (AKs; precancerous lesions that carry a risk of transforming into cSCC) or a single low-risk NMSC
• every 3 months—when there is a history of multiple NMSCs or a single high-risk NMSC
• every 1 to 3 months—when there is a history of metastatic disease.

Continue to: Other risk factors...

Other risk factors for NMSC to consider in SOTRs when determining an appropriate follow-up regimen include any of the following^{1,20,21,24-26}:

• male gender, fair skin, history of childhood sunburn, history of smoking
• lung or heart transplantation, history of episodes of transplant rejection, age ≥ 50 years at transplantation
• immunosuppression with calcineurin inhibitors, compared to mammalian target of rapamycin (mTOR) inhibitors
• immunosuppression with cyclosporine, compared to tacrolimus
• an immunosuppressive regimen with > 1 immunosuppressant or an increased degree of immunosuppression
• antithymocyte globulin within the first year posttransplantation.

Regular screening of skin is important in the solid organ transplant population.

Because the intensity of immunosuppression and individual immunosuppressants used affect the risk of NMSC, conduct a thorough medication review with SOTRs at all visits. Ask about new, changing, or symptomatic (pruritic, painful, bleeding) skin lesions, and perform a full-body skin exam. Palpate draining lymph nodes if the patient has a history of NMSC.¹⁵ AKs (FIGURE 3) should be treated aggressively with liquid nitrogen or field therapy. Lesions suspicious for NMSC should be biopsied and sent for histologic evaluation.²² Shave, punch, and excisional biopsies are all adequate techniques; however, because all cSCCs in SOTRs are considered high risk for aggressive features, biopsy should extend at least into the reticular dermis to allow evaluation for invasive disease.²²

Sun-protective measures (TABLE 1^{1,11,12,15,19-23}). Inquire about patients’ habits related to protection from the sun, their knowledge of recommended sun-protective measures, and risks associated with nonadherence. Recommended sun-protective measures include

• daily broad-spectrum sunscreen (SPF ≥ 30), reapplied every 2 hours of sun exposure, in accordance with labeling instructions²³
• sun-protective clothing (pants, long sleeves, hat, sunglasses)²³
• avoidance of tanning salons.¹⁵

SOTRs who adequately adhere to sun-protective measures might need vitamin D supplementation because sunscreen and sun-protective clothing inhibit cutaneous synthesis of vitamin D.¹⁵

Recommendations for treatment

Consider chemoprophylactic therapy for SOTRs who have had multiple prior cutaneous malignancies or multiple AKs.

Continue to: Topical chemoprophylaxis

Topical medications used for cSCC chemoprophylaxis include 5-fluorouracil (5-FU), photodynamic therapy (PDT), imiquimod, ingenol mebutate, topical retinoids, and diclofenac.²⁷ (See TABLE 2.^27-40) Of these, the latter 3 are used less commonly because of the small packaging size of ingenol mebutate and the relative lack of efficacy data for topical retinoids and diclofenac.²⁷ Imiquimod is often avoided when treating large surface areas because of the risk of systemic adverse effects associated with cytokine release.²⁷

5-FU is US Food and Drug Administration (FDA)-approved for the treatment of AKs, and is used off-label for treating cSCC in situ (Bowen disease). It is the most commonly used topical therapy for field disease.^27-29 5-FU is typically applied once or twice daily for 3 to 4 weeks. Common adverse effects include transient skin irritation and erythema.²⁷

PDT involves topical application of a photosensitizer, such as 5-aminolevulinic acid or methyl aminolevulinate, followed by exposure to a visible light source, leading to antitumor effects on gene expression and destruction of proliferating cells through production of reactive oxygen species.^30,31 Evidence is sufficient to support routine use of PDT for AKs and Bowen disease.³⁰ A mild sunburn-like reaction is common following PDT, with transient erythema and discomfort typically lasting 1 to 2 weeks but not typically necessitating analgesic therapy.²⁷

Imiquimod is a ligand that binds to and activates Toll-like receptor 7, leading to enhancement of the cell-mediated antitumor immune response and resultant tissue-­specific apoptosis coordinated by type 1 T-helper lymphocytes.³² Topical imiquimod cream is FDA approved for field treatment of AKs at 2.5%, 3.75%, and 5% concentrations; efficacy has been demonstrated in the SOTR population.^33,41 Multiple studies in immunocompetent patients have suggested that imiquimod might be slightly less efficacious than 5-FU.^42-44

The tolerability of field treatment with imiquimod has been called into question.²⁷ However, in a 2019 study comparing adverse reactions among 513 immunocompetent patients with field disease who were treated with either 5-FU 5% cream; imiquimod 5% cream; PDT with methyl aminolevulinate; or ingenol mebutate 0.015% gel, a similar or smaller percentage of patients treated with imiquimod reported moderate-to-severe itching, moderate-to-severe pain, and any adverse events, compared to patients treated with the other options.⁴⁴

Continue to: Diclofenac

Diclofenac is a nonsteroidal anti-­inflammatory drug that reversibly inhibits the enzymes cyclooxygenase-1 and ­cyclooxygenase-2, resulting in a decrease in the formation of inflammatory prostaglandins, which have been observed in chronically sun-damaged skin, AKs, and cSCC.^34,45 Diclofenac 3% gel, applied topically twice daily for 60 to 90 days has been approved by the FDA for treatment of AKs, in conjunction with sun avoidance.³⁴ Topical diclofenac has been demonstrated to be efficacious in treating AKs in the SOTR population^46,47; however, multiple meta-analyses using data from immunocompetent patients have demonstrated that topical diclofenac is inferior to other treatment options, particularly 5-FU, at achieving complete clearance of AKs.^43,48,49 Diclofenac might be a useful option when patient adherence is expected to be difficult because of adverse effects of therapy: Multiple studies have suggested that diclofenac might be more tolerable than other options.^43,48,50

Systemic chemoprophylaxis

Systemic therapies that have been used for chemoprophylaxis against cutaneous malignancy include nicotinamide, oral retinoids, capecitabine, and HPV vaccination. (See TABLE 2.^27-40)

Nicotinamide, the amide form of vitamin B₃, protects against cutaneous malignancy by aiding repair of DNA damaged by ionizing radiation, such as UV light.²⁷ Efficacy has been demonstrated in reducing development of new AKs and cSCC in immunocompetent patients with a history of more than 2 keratinocyte carcinomas within a 5-year span.^27,35 Nicotinamide is especially relevant to the SOTR population because it reduces the level of cutaneous immunity suppression induced by UV radiation without altering patients’ baseline immunity.^27,36

Because the intensity of immunosuppression and the individual immunosuppressants used affect the risk of nonmelanoma skin cancer, conduct a thorough medication review at all visits.

There are insufficient long-term follow-up data in the literature to assess the sustainability of the antitumor effects of nicotinamide; studies specific to the SOTR population have been underpowered for assessing its impact on formation of cSCC.^27,35Patients taking nicotinamide should be informed of the risk of liver failure at dosages > 3 g/d (antitumor efficacy has been demonstrated at 500 mg twice daily) and advised to avoid purchasing over-the-counter nicotinic acid or niacin as a substitute for nicotinamide, because of the increased incidence of flushing associated with their use.²⁷

Oral retinoids. Systemic retinoids—in particular, acitretin—are efficacious in reducing the risk of cSCC in SOTRs.^27,37,38 The primary drawback to cSCC prophylaxis with oral retinoids is a rebound effect, in which treatment discontinuation leads to a rapid return to baseline cSCC formation.²⁷

Continue to: Pregnancy must be avoided...

Pregnancy must be avoided while taking an oral retinoid. Because acitretin can persist in the body for years after discontinuation, its use should generally be avoided in patients of childbearing potential. An FDA black box warning states that patients of childbearing potential must be counseled to use 2 forms of birth control to avoid pregnancy for ≥ 3 years after cessation of oral acitretin. Prior to initiation of oral retinoid therapy, the following baseline laboratory tests should be obtained: complete blood count, creatinine, lipid panel, and liver function tests. For patients with a history of chronic kidney disease or renal transplantation, the lipid panel, liver function tests, and creatinine assay should be repeated with each dosage adjustment and every 3 months once goal-dosing is achieved.²⁷

Capecitabine is typically initiated with the help of Medical Oncology.^27,40 A prodrug metabolized by dihydropyrimidine dehydrogenase to 5-FU, capecitabine interacts with warfarin, leading to a significant increase in prothrombin time.³⁹ Other adverse effects associated with oral capecitabine include fatigue, palmar-plantar erythrodysesthesia, diarrhea, and, rarely, neutropenia. Although dihydropyrimidine dehydrogenase deficiency is rare, treatment with capecitabine in patients who have this enzyme deficiency might lead to severe toxicity or death.²⁷

HPV vaccination. HPV might play a role in the development of cutaneous malignancy, especially in immunosuppressed patients.^4,5 The utility of HPV vaccination in the prevention of NMSC has yet to be determined, but vaccination has been shown, in case reports, to be helpful in immunocompetent patients.^51,52 The immunogenicity of HPV vaccination in the SOTR population is uncertain, and the most common HPV types found in SOTRs are not specifically covered by available HPV vaccines.¹⁹

The role of immunosuppression reduction and immunosuppressive replacement

Both the degree of immunosuppression and the individual agents used can affect a patient’s risk of NMSC. Immunosuppression reduction should be considered if skin cancer poses a major risk to the patient’s health and if that risk outweighs the risk of graft rejection associated with immunosuppression reduction.²⁷ In a cohort of 180 kidney and liver SOTRs who developed de novo carcinoma (excluding NMSC) after transplantation, neither reduction of immunosuppression nor introduction of an mTOR inhibitor affected graft survival or oncologic treatment tolerance.⁵³ Because mTOR inhibitors have a protective effect against development of NMSC, they are the preferred choice of immunosuppressive agent from a dermatologic perspective.^1,27,54-57 Decisions regarding changes in immunosuppression are generally made by, or in collaboration with, the patient’s transplant physician.

Recommendations: Treating cSCC

Risk should guide strategy

Consider chemoprophylactic therapy for solid organ transplant recipients who have had multiple prior cutaneous malignancies or multiple AKs.

Small lesions of the trunk and extremities without high-risk features can be treated with a destructive method (eg, electrodessication and curettage). However, lesions of the head and neck and those found to have features consistent with an increased risk of recurrence or metastasis should be treated aggressively.^3,58,59

Continue to: Risk factors for invasive growth...

Risk factors for invasive growth, recurrence, or metastasis of cSCC in SOTRs are multiple lesions or satellite lesions, indistinct clinical borders, rapid growth, ulceration, and recurrence after treatment.⁶⁰ The risk of invasive growth, recurrence, and metastasis of cSCC also increases with size and location of the lesion, according to this framework⁶⁰:

• any size in scar tissue, areas of chronic inflammation, and fields of prior radiation therapy
• ≥ 0.6 cm on hands, feet, genitalia, and mask areas of the face (central face, eyelids, eyebrows, nose, lips, chin, mandible, and temporal, preauricular, postauricular, and periorbital areas)
• > 1 cm on cheeks, forehead, neck, and scalp
• > 2 cm on the trunk and extremities.

In addition, specific findings on histologic analysis portend increased risk of invasive growth, recurrence, or metastasis:

• poor differentiation
• deep extension of the tumor into subcutaneous fat
• perineural invasion or inflammation
• perivascular or intravascular invasion.

Treatment modalities

Mohs surgery is preferred to ensure margin clearance while preserving noninvolved tissue^3,7 (FIGURE 4). If Mohs surgery is not possible, the lesion should be excised with 3- to 10-mm margins.^3,60 Based on current literature, the roles of nodal staging, sentinel lymph node biopsy, and adjuvant therapy are not well defined, but it is likely that these interventions will play a pivotal role in the management of advanced cSCC in SOTRs in the future.³

Pregnancy must be avoided while taking an oral retinoid; because of its persistence, acitretin should generally be avoided in patients of childbearing potential.

Nonsurgical therapeutic options for primary or adjuvant treatment of cSCC include systemic chemotherapy, radiotherapy, and programmed cell death protein 1 inhibitors. (For more on treatment modalities, see TABLE 3.^3,7,58-61)

Recommendations: Treating BCC

BCC in SOTRs is treated similarly (TABLE 3^3,7,58-61) to how it is treated in the immunocompetent population—except that SOTRs require closer follow-up than nontransplant patients because they are at higher risk of recurrence and new NMSCs.³ Standard management after biopsy is either^3,61:

• Mohs surgery to ensure margin control (for most BCCs on the head and neck and those with clinical or histologic risk factors for recurrence or aggressive behavior)
• excision with a 4- or 5-mm margin or a destructive modality (for BCCs on the trunk and extremities without risk factors for recurrence).

Radiotherapy is an alternative for patients with high-risk BCCs who are unable to tolerate surgery.³

CORRESPONDENCE
Lindsey Collins, MD, Department of Dermatology, University of Oklahoma Health Sciences Center, 619 NE 13th Steet, Oklahoma City, OK 73104; [email protected]

The incidence of posttransplant malignancy among solid organ transplant recipients (SOTRs) is 10%; skin cancer, primarily nonmelanoma skin cancer (NMSC), constitutes 49.5% of all malignancies in this population.¹ The etiology of the increased risk of cutaneous malignancy in SOTR is multifactorial:

• The skin of SOTRs is photosensitive, compared to that of immunocompetent patients, thus predisposing SOTRs to carcinogenic damage resulting from exposure to UV light.²
• Immunosuppression plays a key role in increasing the risk of cutaneous malignancy by inhibiting the ability of the immune system to recognize and destroy tumor cells.³
• Human papillomavirus (HPV) can play a role in carcinogenesis by promoting molecular pathways to proliferation and survival of nascent tumor cells⁴;Times New Romanβ-HPV strains are disseminated ubiquitously in the skin of immunosuppressed patients.⁵
• Some medications administered after transplantation can be directly carcinogenic.

NMSC in SOTRs also differs qualitatively from NMSC in immunocompetent patients. Cutaneous squamous cell carcinoma (cSCC) (FIGUREs 1 and 2) is the most common skin cancer among SOTRs, whereas basal cell carcinoma (BCC) is the most common skin cancer in the general population.³ cSCC in the SOTR population tends to be more aggressive, with more rapid local invasion and an increased rate of both in-transit and distant metastases, leading to an increase in morbidity and mortality. Mortality of metastatic cSCC among SOTRs is approximately 50%, compared to 20% in an otherwise healthy population.^3,6-8

The problem is relevant to primary care

Screening. Because there is a demonstrated reduction in morbidity and mortality associated with early detection and treatment of NMSC, regular screening of skin is important in the SOTR population.⁹ A study in Ontario, Canada, from 1994 to 2012 and comprising 10,183 SOTRs, found that adherence to an annual skin check regimen for ≥ 75% of the observation period was associated with a 34% reduction in cutaneous BCC- and cSCC-­related morbidity or death (adjusted hazard ratio = 0.66; 95% CI, 0.48-0.92).¹⁰ Although routine follow-up with a dermatologist is recommended for SOTRs,^9,11-15 only 2.1% of patients in the Canadian study were fully adherent with annual skin examination, and 55% never visited a dermatologist.¹⁰ Consequently, primary care physicians can play a key role in skin cancer screening for SOTRs.

Education regarding the importance of protection from the sun is also an essential part of primary care. A 2018 study of SOTRs in Turkey demonstrated that¹⁶

• 46% expressed a lack of knowledge of the hazards of sun exposure
• 44% did not recall ever receiving medical advice regarding sun protection
• 89% did not wear sun-protective clothing
• 86% did not use sunscreen daily.

Multiple studies have demonstrated the positive effect that preventive education and attendance at a dermatology or skin cancer screening clinic can have on sun-protective behaviors among SOTRs.^9,16-18 In the Turkish study, 100% of patients who reported using sunscreen daily had been undergoing regular dermatologic examination.¹⁶

In this article, we review current management guidelines regarding the prevention and treatment of NMSC in SOTRs.

Recommendations for prevention

Screening skin exams (TABLE 1^{1,11,12,15,19-23}). Although definitive guidelines do not exist regarding the frequency of a screening skin exam for SOTRs, multiple frequency-­determining algorithms have been proposed.^11,12,15,19 The recommended frequency of a skin exam is based on history of skin cancer; for SOTRs, the most common recommendation¹⁹ is a full-body skin examination as follows:

• annually—when there is no history of skin cancer
• every 6 months—when there is a history of actinic keratoses (AKs; precancerous lesions that carry a risk of transforming into cSCC) or a single low-risk NMSC
• every 3 months—when there is a history of multiple NMSCs or a single high-risk NMSC
• every 1 to 3 months—when there is a history of metastatic disease.

Continue to: Other risk factors...

Other risk factors for NMSC to consider in SOTRs when determining an appropriate follow-up regimen include any of the following^{1,20,21,24-26}:

• male gender, fair skin, history of childhood sunburn, history of smoking
• lung or heart transplantation, history of episodes of transplant rejection, age ≥ 50 years at transplantation
• immunosuppression with calcineurin inhibitors, compared to mammalian target of rapamycin (mTOR) inhibitors
• immunosuppression with cyclosporine, compared to tacrolimus
• an immunosuppressive regimen with > 1 immunosuppressant or an increased degree of immunosuppression
• antithymocyte globulin within the first year posttransplantation.

Regular screening of skin is important in the solid organ transplant population.

Because the intensity of immunosuppression and individual immunosuppressants used affect the risk of NMSC, conduct a thorough medication review with SOTRs at all visits. Ask about new, changing, or symptomatic (pruritic, painful, bleeding) skin lesions, and perform a full-body skin exam. Palpate draining lymph nodes if the patient has a history of NMSC.¹⁵ AKs (FIGURE 3) should be treated aggressively with liquid nitrogen or field therapy. Lesions suspicious for NMSC should be biopsied and sent for histologic evaluation.²² Shave, punch, and excisional biopsies are all adequate techniques; however, because all cSCCs in SOTRs are considered high risk for aggressive features, biopsy should extend at least into the reticular dermis to allow evaluation for invasive disease.²²

Sun-protective measures (TABLE 1^{1,11,12,15,19-23}). Inquire about patients’ habits related to protection from the sun, their knowledge of recommended sun-protective measures, and risks associated with nonadherence. Recommended sun-protective measures include

• daily broad-spectrum sunscreen (SPF ≥ 30), reapplied every 2 hours of sun exposure, in accordance with labeling instructions²³
• sun-protective clothing (pants, long sleeves, hat, sunglasses)²³
• avoidance of tanning salons.¹⁵

SOTRs who adequately adhere to sun-protective measures might need vitamin D supplementation because sunscreen and sun-protective clothing inhibit cutaneous synthesis of vitamin D.¹⁵

Recommendations for treatment

Consider chemoprophylactic therapy for SOTRs who have had multiple prior cutaneous malignancies or multiple AKs.

Continue to: Topical chemoprophylaxis

Topical medications used for cSCC chemoprophylaxis include 5-fluorouracil (5-FU), photodynamic therapy (PDT), imiquimod, ingenol mebutate, topical retinoids, and diclofenac.²⁷ (See TABLE 2.^27-40) Of these, the latter 3 are used less commonly because of the small packaging size of ingenol mebutate and the relative lack of efficacy data for topical retinoids and diclofenac.²⁷ Imiquimod is often avoided when treating large surface areas because of the risk of systemic adverse effects associated with cytokine release.²⁷

5-FU is US Food and Drug Administration (FDA)-approved for the treatment of AKs, and is used off-label for treating cSCC in situ (Bowen disease). It is the most commonly used topical therapy for field disease.^27-29 5-FU is typically applied once or twice daily for 3 to 4 weeks. Common adverse effects include transient skin irritation and erythema.²⁷

PDT involves topical application of a photosensitizer, such as 5-aminolevulinic acid or methyl aminolevulinate, followed by exposure to a visible light source, leading to antitumor effects on gene expression and destruction of proliferating cells through production of reactive oxygen species.^30,31 Evidence is sufficient to support routine use of PDT for AKs and Bowen disease.³⁰ A mild sunburn-like reaction is common following PDT, with transient erythema and discomfort typically lasting 1 to 2 weeks but not typically necessitating analgesic therapy.²⁷

Imiquimod is a ligand that binds to and activates Toll-like receptor 7, leading to enhancement of the cell-mediated antitumor immune response and resultant tissue-­specific apoptosis coordinated by type 1 T-helper lymphocytes.³² Topical imiquimod cream is FDA approved for field treatment of AKs at 2.5%, 3.75%, and 5% concentrations; efficacy has been demonstrated in the SOTR population.^33,41 Multiple studies in immunocompetent patients have suggested that imiquimod might be slightly less efficacious than 5-FU.^42-44

The tolerability of field treatment with imiquimod has been called into question.²⁷ However, in a 2019 study comparing adverse reactions among 513 immunocompetent patients with field disease who were treated with either 5-FU 5% cream; imiquimod 5% cream; PDT with methyl aminolevulinate; or ingenol mebutate 0.015% gel, a similar or smaller percentage of patients treated with imiquimod reported moderate-to-severe itching, moderate-to-severe pain, and any adverse events, compared to patients treated with the other options.⁴⁴

Continue to: Diclofenac

Diclofenac is a nonsteroidal anti-­inflammatory drug that reversibly inhibits the enzymes cyclooxygenase-1 and ­cyclooxygenase-2, resulting in a decrease in the formation of inflammatory prostaglandins, which have been observed in chronically sun-damaged skin, AKs, and cSCC.^34,45 Diclofenac 3% gel, applied topically twice daily for 60 to 90 days has been approved by the FDA for treatment of AKs, in conjunction with sun avoidance.³⁴ Topical diclofenac has been demonstrated to be efficacious in treating AKs in the SOTR population^46,47; however, multiple meta-analyses using data from immunocompetent patients have demonstrated that topical diclofenac is inferior to other treatment options, particularly 5-FU, at achieving complete clearance of AKs.^43,48,49 Diclofenac might be a useful option when patient adherence is expected to be difficult because of adverse effects of therapy: Multiple studies have suggested that diclofenac might be more tolerable than other options.^43,48,50

Systemic chemoprophylaxis

Systemic therapies that have been used for chemoprophylaxis against cutaneous malignancy include nicotinamide, oral retinoids, capecitabine, and HPV vaccination. (See TABLE 2.^27-40)

Nicotinamide, the amide form of vitamin B₃, protects against cutaneous malignancy by aiding repair of DNA damaged by ionizing radiation, such as UV light.²⁷ Efficacy has been demonstrated in reducing development of new AKs and cSCC in immunocompetent patients with a history of more than 2 keratinocyte carcinomas within a 5-year span.^27,35 Nicotinamide is especially relevant to the SOTR population because it reduces the level of cutaneous immunity suppression induced by UV radiation without altering patients’ baseline immunity.^27,36

Because the intensity of immunosuppression and the individual immunosuppressants used affect the risk of nonmelanoma skin cancer, conduct a thorough medication review at all visits.

There are insufficient long-term follow-up data in the literature to assess the sustainability of the antitumor effects of nicotinamide; studies specific to the SOTR population have been underpowered for assessing its impact on formation of cSCC.^27,35Patients taking nicotinamide should be informed of the risk of liver failure at dosages > 3 g/d (antitumor efficacy has been demonstrated at 500 mg twice daily) and advised to avoid purchasing over-the-counter nicotinic acid or niacin as a substitute for nicotinamide, because of the increased incidence of flushing associated with their use.²⁷

Oral retinoids. Systemic retinoids—in particular, acitretin—are efficacious in reducing the risk of cSCC in SOTRs.^27,37,38 The primary drawback to cSCC prophylaxis with oral retinoids is a rebound effect, in which treatment discontinuation leads to a rapid return to baseline cSCC formation.²⁷

Continue to: Pregnancy must be avoided...

Pregnancy must be avoided while taking an oral retinoid. Because acitretin can persist in the body for years after discontinuation, its use should generally be avoided in patients of childbearing potential. An FDA black box warning states that patients of childbearing potential must be counseled to use 2 forms of birth control to avoid pregnancy for ≥ 3 years after cessation of oral acitretin. Prior to initiation of oral retinoid therapy, the following baseline laboratory tests should be obtained: complete blood count, creatinine, lipid panel, and liver function tests. For patients with a history of chronic kidney disease or renal transplantation, the lipid panel, liver function tests, and creatinine assay should be repeated with each dosage adjustment and every 3 months once goal-dosing is achieved.²⁷

Capecitabine is typically initiated with the help of Medical Oncology.^27,40 A prodrug metabolized by dihydropyrimidine dehydrogenase to 5-FU, capecitabine interacts with warfarin, leading to a significant increase in prothrombin time.³⁹ Other adverse effects associated with oral capecitabine include fatigue, palmar-plantar erythrodysesthesia, diarrhea, and, rarely, neutropenia. Although dihydropyrimidine dehydrogenase deficiency is rare, treatment with capecitabine in patients who have this enzyme deficiency might lead to severe toxicity or death.²⁷

HPV vaccination. HPV might play a role in the development of cutaneous malignancy, especially in immunosuppressed patients.^4,5 The utility of HPV vaccination in the prevention of NMSC has yet to be determined, but vaccination has been shown, in case reports, to be helpful in immunocompetent patients.^51,52 The immunogenicity of HPV vaccination in the SOTR population is uncertain, and the most common HPV types found in SOTRs are not specifically covered by available HPV vaccines.¹⁹

The role of immunosuppression reduction and immunosuppressive replacement

Both the degree of immunosuppression and the individual agents used can affect a patient’s risk of NMSC. Immunosuppression reduction should be considered if skin cancer poses a major risk to the patient’s health and if that risk outweighs the risk of graft rejection associated with immunosuppression reduction.²⁷ In a cohort of 180 kidney and liver SOTRs who developed de novo carcinoma (excluding NMSC) after transplantation, neither reduction of immunosuppression nor introduction of an mTOR inhibitor affected graft survival or oncologic treatment tolerance.⁵³ Because mTOR inhibitors have a protective effect against development of NMSC, they are the preferred choice of immunosuppressive agent from a dermatologic perspective.^1,27,54-57 Decisions regarding changes in immunosuppression are generally made by, or in collaboration with, the patient’s transplant physician.

Recommendations: Treating cSCC

Risk should guide strategy

Consider chemoprophylactic therapy for solid organ transplant recipients who have had multiple prior cutaneous malignancies or multiple AKs.

Small lesions of the trunk and extremities without high-risk features can be treated with a destructive method (eg, electrodessication and curettage). However, lesions of the head and neck and those found to have features consistent with an increased risk of recurrence or metastasis should be treated aggressively.^3,58,59

Continue to: Risk factors for invasive growth...

Risk factors for invasive growth, recurrence, or metastasis of cSCC in SOTRs are multiple lesions or satellite lesions, indistinct clinical borders, rapid growth, ulceration, and recurrence after treatment.⁶⁰ The risk of invasive growth, recurrence, and metastasis of cSCC also increases with size and location of the lesion, according to this framework⁶⁰:

• any size in scar tissue, areas of chronic inflammation, and fields of prior radiation therapy
• ≥ 0.6 cm on hands, feet, genitalia, and mask areas of the face (central face, eyelids, eyebrows, nose, lips, chin, mandible, and temporal, preauricular, postauricular, and periorbital areas)
• > 1 cm on cheeks, forehead, neck, and scalp
• > 2 cm on the trunk and extremities.

In addition, specific findings on histologic analysis portend increased risk of invasive growth, recurrence, or metastasis:

• poor differentiation
• deep extension of the tumor into subcutaneous fat
• perineural invasion or inflammation
• perivascular or intravascular invasion.

Treatment modalities

Mohs surgery is preferred to ensure margin clearance while preserving noninvolved tissue^3,7 (FIGURE 4). If Mohs surgery is not possible, the lesion should be excised with 3- to 10-mm margins.^3,60 Based on current literature, the roles of nodal staging, sentinel lymph node biopsy, and adjuvant therapy are not well defined, but it is likely that these interventions will play a pivotal role in the management of advanced cSCC in SOTRs in the future.³

Pregnancy must be avoided while taking an oral retinoid; because of its persistence, acitretin should generally be avoided in patients of childbearing potential.

Nonsurgical therapeutic options for primary or adjuvant treatment of cSCC include systemic chemotherapy, radiotherapy, and programmed cell death protein 1 inhibitors. (For more on treatment modalities, see TABLE 3.^3,7,58-61)

Recommendations: Treating BCC

BCC in SOTRs is treated similarly (TABLE 3^3,7,58-61) to how it is treated in the immunocompetent population—except that SOTRs require closer follow-up than nontransplant patients because they are at higher risk of recurrence and new NMSCs.³ Standard management after biopsy is either^3,61:

• Mohs surgery to ensure margin control (for most BCCs on the head and neck and those with clinical or histologic risk factors for recurrence or aggressive behavior)
• excision with a 4- or 5-mm margin or a destructive modality (for BCCs on the trunk and extremities without risk factors for recurrence).

Radiotherapy is an alternative for patients with high-risk BCCs who are unable to tolerate surgery.³

CORRESPONDENCE
Lindsey Collins, MD, Department of Dermatology, University of Oklahoma Health Sciences Center, 619 NE 13th Steet, Oklahoma City, OK 73104; [email protected]

An estimated 20 million patients in the United States have a substance use disorder (SUD), with hundreds of millions of prescriptions for controlled substances written annually. Consequently, urine drug screening (UDS) has become widely utilized to evaluate and treat patients with an SUD or on chronic opioid or benzodiazepine therapy.¹

Used appropriately, UDS can be a valuable tool; there is ample evidence, however, that it has been misused, by some physicians, to stigmatize patients who use drugs of abuse,² profile patients racially,² profit from excessive testing,³ and inappropriately discontinue treatment.⁴

A patient-centered approach. We have extensive clinical experience in the use and interpretation of urine toxicology, serving as clinical leads in busy family medicine residency practices that care for patients with SUDs, and are often consulted regarding patients on chronic opioid or benzodiazepine therapy. We have encountered countless situations in which the correct interpretation of UDS is critical to providing care.

Over time, and after considerable trial and error, we developed the patient-centered approach to urine toxicology described in this article. We believe that the medical evidence strongly supports our approach to the appropriate use and interpretation of urine toxicology in clinical practice. Our review here is intended as a resource when you consider implementing a UDS protocol or are struggling with the management of unexpected results.

Urine toxicology for therapeutic drug monitoring

Prescribing a controlled substance carries inherent risks, including diversion, nonmedical use, and development of an SUD. Prescribed medications, particularly opioids and benzodiazepines, have been linked to a large increase in overdose deaths over the past decade.⁵ Several strategies have been investigated to mitigate risk (see “How frequently should a patient be tested?,” later in the article).

Clinical judgment—ie, when a physician orders a drug test upon suspecting that a patient is diverting a prescribed drug or has developed a substance use disorder—has been shown to be highly inaccurate.

Clinical judgment—ie, when a physician orders a drug test upon suspecting that a patient is diverting a prescribed drug or has developed an SUD—has been shown to be highly inaccurate. Implicit racial bias might affect the physician’s judgment, leading to changes in testing and test interpretation. For example, Black patients were found to be 10% more likely to have drug screening ordered while being treated with long-term opioid therapy and 2 to 3 times more likely to have their medication discontinued as a result of a marijuana- or cocaine-positive test.²

Other studies have shown that testing patients for “bad behavior,” so to speak—reporting a prescription lost or stolen, consuming more than the prescribed dosage, visiting the office without an appointment, having multiple drug intolerances and allergies, and making frequent telephone calls to the practice—is ineffective.⁶ Patients with these behaviors were slightly more likely to unexpectedly test positive, or negative, on their UDS; however, many patients without suspect behavior also were found to have abnormal toxicology results.⁶ Data do not support therapeutic drug monitoring only of patients selected on the basis of aberrant behavior.⁶

Continue to: Questions and concerns about urine drug screening

Why not just ask the patient? Studies have evaluated whether patient self-reporting of adherence is a feasible alternative to laboratory drug screening. Regrettably, patients have repeatedly been shown to underreport their use of both prescribed and illicit drugs.^7,8

That question leads to another: Why do patients lie to their physician? It is easy to assume malicious intent, but a variety of obstacles might dissuade a patient from being fully truthful with their physician:

• Monetary gain. A small, but real, percentage of medications are diverted by patients for this reason.⁹
• Addiction, pseudo-addiction due to tolerance, and self-medication for psychological symptoms are clinically treatable syndromes that can lead to underreporting of prescribed and nonprescribed drug and alcohol use.
• Shame. Addiction is a highly stigmatized disease, and patients might simply be ashamed to admit that they need treatment: 13% to 38% of patients receiving chronic opioid therapy in a pain management or primary care setting have a clinically diagnosable SUD.^10,11

Is consent needed to test or to share test results? Historically, UDS has been performed on patients without their consent or knowledge.¹² Patients give a urine specimen to their physician for a variety of reasons; it seems easy to “add on” UDS. Evidence is clear, however, that confronting a patient about an unexpected test result can make the clinical outcome worse—often resulting in irreparable damage to the patient–­physician relationship.^12,13 Unless the patient is experiencing a medical emergency, guidelines unanimously recommend obtaining consent prior to testing.^1,5,14

Annual screening is appropriate in low-risk patients; moderate-risk patients should be screened twice a year, and high-risk patients should be screened at least every 4 months.

Federal law requires written permission from the patient for the physician to disclose information about alcohol or substance use, unless the information is expressly needed to provide care during a medical emergency. Substance use is highly stigmatized, and patients might—legitimately—fear that sharing their history could undermine their care.^1,12,14

How frequently should a patient be tested? Experts recommend utilizing a risk-based strategy to determine the frequency of UDS.^1,5,15 Validated risk-assessment questionnaires include:

• Opioid Risk Tool for Opioid Use Disorder (ORT-OUD)^a
• Screener and Opioid Assessment for Patients With Pain–Revised (SOAPP-R)^b
• Diagnosis, Intractability, Risk and Efficacy (DIRE)^c
• Addiction Behaviors Checklist (ABC).^d

Continue to: Each of these tools...

Each of these tools takes less than 5 minutes to administer and can be used by a primary care physician to objectively quantify the risk of prescribing; there is no evidence for the use of 1 of these screeners over the others.¹⁵ It is recommended that you choose a questionnaire that works for you and incorporate the risk assessment into prescribing any high-risk medication.^1,5,15

Once you have completed an initial risk assessment, the frequency of UDS can be based on ongoing assessment that incorporates baseline testing, patient self-reporting, toxicology results, behavioral monitoring, and state database monitoring through a prescription drug monitoring program. Annual screening is appropriate in low-risk patients; moderate-risk patients should be screened twice a year, and high-risk patients should be screened at least every 4 months (FIGURE).¹⁵

Many state and federal agencies, health systems, employers, and insurers mandate the frequency of testing through guidelines or legislation. These regulations often are inconsistent with the newest medical evidence.¹⁵ Consult local guidelines and review the medical evidence and consensus recommendations on UDS.

What are the cost considerations in providing UDS? Insurers have been billed as much as $4000 for definitive chromatography testing (described later).³ This has led to insurance fraud, when drug-testing practices with a financial interest routinely use large and expensive test panels, test too frequently, or unnecessarily send for confirmatory or quantitative analysis of all positive tests.^3,14 Often, insurers refuse to pay for unnecessary testing, leaving patients with significant indebtedness.^3,14 Take time to review the evidence and consensus recommendations on UDS to avoid waste, potential accusations of fraud, and financial burden on your patients.

Urine toxicology for addiction treatment

UDS protocols in addiction settings are often different from those in which a controlled substance is being prescribed.

Continue to: Routine and random testing

Routine and random testing. Two common practices when treating addiction are to perform UDS on all patients, at every visit, or to test randomly.¹ These practices can be problematic, however. Routine testing at every visit can make urine-tampering more likely and is often unnecessary for stable patients. Random testing can reduce the risk of urine-tampering, but it is often difficult for primary care clinics to institute such a protocol. Some clinics have patients provide a urine specimen at every visit and then only send tests to the lab based on randomization.¹

Contingency management—a behavioral intervention in which a patient is rewarded, or their performance is reinforced, when they display evidence of positive change—is the most effective strategy used in addiction medicine to determine the frequency of patient visits and UDS.^14,16 High-risk patients with self-reported active substance use or UDS results consistent with substance use, or both, are seen more often; as their addiction behavior diminishes, visits and UDS become less frequent. If addiction behavior increases, the patient is seen more often. Keep in mind that addiction behavior decreases over months of treatment, not immediately upon initiation.^14,17 For contingency management to be successful, patient-centered interviewing and UDS will need to be employed frequently as the patient works toward meaningful change.¹⁴

The technology of urine drug screening

Two general techniques are used for UDS: immunoassay and chromatography. Each plays an important role in clinical practice; physicians must therefore maintain a basic understanding of the mechanism of each technique and their comparable advantages and disadvantages. Such an understanding allows for (1) matching the appropriate technique to the individual clinical scenario and (2) correctly interpreting results.

Immunoassay technology is used for point-of-care and rapid laboratory UDS, using antibodies to detect the drug or drug metabolite of interest. Antibodies utilized in immunoassays are designed to selectively bind a specific antigen—ie, a unique chemical structure within the drug of choice. Once bound, the antigen–antibody complex can be exploited for detection through various methods.

Chromatography–mass ­spectrometry is considered the gold standard for UDS, yielding confirmatory results. This is a 2-step process: Chromatography separates components within a specimen; mass spectrometry then identifies those components. Most laboratories employ liquid, rather than gas, chromatography. The specificity of the liquid chromatography–mass spectrometry method is such that a false-positive result is, essentially, impossible.¹⁸

Continue to: How is the appropriate tests elected for urine drug screening?

Variables that influence your choice of the proper test method include the clinical question at hand; cost; the urgency of obtaining results; and the stakes in that decision (ie, will the results be used to simply change the dosage of a medication or, of greater consequence, to determine fitness for employment or inform criminal justice decisions?). Each method of UDS has advantages that can be utilized and disadvantages that must be considered to obtain an accurate and useful result.

Immunoassay provides rapid results, is relatively easy to perform, and is, comparatively, inexpensive.^1,14 The speed of results makes this method particularly useful in settings such as the emergency department, where rapid results are crucial. Ease of use makes immunoassay ideal for the office, where non-laboratory staff can be trained to properly administer the test.

A major disadvantage of immunoassay technology, however, is interference resulting in both false-positive and false-negative results, which is discussed in detail in the next section. Immunoassay should be considered a screening test that yields presumptive results.

Liquid chromatography–mass spectrometry is exquisitely specific and provides confirmatory test results—major advantages of the method. However, specificity comes at a price: significantly increased cost and longer wait time for results (typically days, if specimens are sent out to a laboratory). These barriers can make it impractical to employ this method in routine practice.

Interpretation of results: Not so fast

Interpreting UDS results is not as simple as noting a positive or negative result. Physicians must understand the concept of interference, so that results can be appropriately interpreted and confirmed. This is crucial when results influence clinical decisions; inappropriate action, taken on the basis of presumptive results, can have severe consequences for the patient–provider relationship and the treatment plan.^1,14

Continue to: Interference falls into 2 categories...

Interference falls into 2 categories: variables inherent in the testing process and patient variables.

Obtain consent prior to performing urine drug screening, even if you are already collecting a specimen for other testing.

Antibody cross-reactivity. A major disadvantage of immunoassay technology is interference that results in false-positive and false-negative results.^19,20 The source of this interference is antibody cross-­reactivity—the degree to which an antibody binds to structurally similar compounds. Antibody–­antigen interactions are incredibly complex; although assay antibodies are engineered to specifically detect a drug class of interest, reactivity with other, structurally similar compounds is unavoidable.

Nevertheless, cross-reactivity is a useful phenomenon that allows broad testing for multiple drugs within a class. For example, most point-of-care tests for benzodiazepines reliably detect diazepam and chlordiazepoxide. Likewise, opiate tests reliably detect natural opiates, such as morphine and codeine. Cross-reactivity is not limitless, however; most benzodiazepine immunoassays have poor reactivity to clonazepam and lorazepam, making it possible that a patient taking clonazepam tests negative for benzodiazepine on an immunoassay.^14,20 Similarly, standard opioid tests have only moderate cross-reactivity for semisynthetic opioids, such as hydrocodone and hydromorphone; poor cross-r­eactivity for oxycodone and oxymorphone; and essentially no cross-­reactivity for full synthetics, such as fentanyl and methadone.¹⁴

It is the responsibility of the ordering physician to understand cross-reactivity to various drugs within a testing class.

Routine urine drug screening at every visit can make urine tampering more likely and is often unnecessary for stable patients.

Whereas weak cross-reactivity to drugs within a class can be a source of false-negative results, cross-reactivity to drugs outside the class of interest is a source of false-positive results. An extensive review of drugs that cause false-positive immunoassay screening tests is outside the scope of this article; commonly prescribed medications implicated in false-positive results are listed in TABLE 1.¹⁹

Continue to: In general...

In general, amphetamine immunoassays produce frequent false-positive results, whereas cocaine and cannabinoid assays are more specific.^1,18 Common over-the-counter medications, including nonsteroidal anti-inflammatory drugs, decongestants, and antacids, can yield false-positive results, highlighting the need to obtain a comprehensive medication list from patients, including over-the-counter and herbal medications, before ordering UDS. Because of the complexity of cross-reactivity, it might not be possible to identify the source of a false-positive result.¹⁴

Patient variables. Intentional effort to skew results is another source of interference. The frequency of this effort varies by setting and the potential consequences of results—eg, employment testing or substance use treatment—and a range of attempts have been reported in the literature.^21,22 Common practices are dilution, adulteration, and substitution.^20,23

• Dilution lowers the concentration of the drug of interest below the detection limit of the assay by directly adding water to the urine specimen, drinking copious amounts of fluid, taking a diuretic, or a combination of these practices.
• Adulteration involves adding a substance to urine that interferes with the testing mechanism: for example, bleach, household cleaners, eye drops, and even commercially available products expressly marketed to interfere with UDS.²⁴
• Substitution involves providing urine or a urine-like substance for testing that did not originate from the patient.

Methods to minimize patient-related interference include observed collection and specimen validity testing for pH, creatinine, and adulterants (TABLE 2).^1,15 Efforts to detect patient interference must be balanced against concerns about privacy, personnel resources, and the cost of expanded testing.^14,19,20

Additional aspects inherent to the testing process, such as cutoff concentrations and detection windows, can lead to interference. Laboratories must set reporting cutoffs, and specimens with a drug concentration present but below the cutoff value are reported as a negative result. Detection windows are complex and are influenced by inherent properties of the drug, including metabolic pathway and route and frequency of use.¹ A given patient might well be using a substance, but if the specimen was obtained outside the detection window, a false-negative result might be reported (TABLE 3^1,23).

Managing test results

Appropriate management of UDS results is built on the foundation of understanding the testing mechanism, selecting the correct test, and properly interpreting results. Drug testing is, ultimately, a therapeutic tool used to monitor treatment, provide reinforcement, and explore substance use behavior; results of testing should be employed to achieve those objectives.^1,4,14 A negative or expected UDS result can be utilized as positive reinforcement for a patient who is adherent to the treatment plan—much the way objective weight loss in an obese patient can provide encouragement to continue lifestyle changes.

Continue to: Test results should be presented...

Test results should be presented in an objective, nonconfrontational, and compassionate manner, not with stigmatizing language, such as “clean” or “dirty.”^1,13,14 Using stigmatizing terms such as “substance abuser” instead of “person with a substance use disorder” has been shown, even among highly trained health care professionals, to have a negative effect on patient care.¹³

A given patient might well be using a substance, but if the specimen was obtained outside the detection window, a false-negative result might be reported.

Inevitably, you will encounter an unexpected result, and therefore must develop a rational, systematic, and compassionate management approach. “Unexpected result” is a broad term that includes results that conflict with

• a patient’s self-report
• your understanding of what the patient is taking (using)
• prescribed medications
• a patient’s typical substance use pattern.

When faced with an unexpected test result, first, ensure that the result in question is reliable. If a screening test yields an unanticipated finding—especially if it conflicts with the patient’s self-reporting—make every effort to seek confirmation if you are going to be making a significant clinical decision because of the result.^1,14

Second, use your understanding of interference to consider the result in a broader context. If confirmatory results are inconsistent with a patient’s self-report, discuss whether there has been a break in the ­ph­ysician–patient relationship and emphasize that recurrent use or failure to adhere to a treatment plan has clear consequences.^1,14 Modify the treatment plan to address the inconsistent finding by escalating care, adjusting medications, and connecting the patient to additional resources.

Third, keep in mind that a positive urine test is not diagnostic of an SUD. Occasional drug use is extremely common¹⁷ and should not categorically lead to a change in the treatment plan. Addiction is, fundamentally, a disease of disordered reward, motivation, and behavior that is defined by the consequences of substance use, not substance use per se,²⁵ and an SUD diagnosis is complex, based on clinical history, physical examination, and laboratory testing. Similarly, a negative UDS result does not rule out an SUD.^4,10

Continue to: Fourth, patient dismissal...

Fourth, patient dismissal is rarely an appropriate initial response to UDS results. Regrettably, some physicians misinterpret urine toxicology results and inappropriately discharge patients on that basis.

In general, amphetamine immunoassays produce frequent falsepositive results, whereas cocaine and cannabinoid assays are more specific.

The Centers for Disease Control and Prevention guideline for prescribing opioids has increased utilization of UDS in primary care settings but does not provide the necessary education on proper use of the tool, which has resulted in a rise in misinterpretation and inappropriate discharge.^13,26

If recurrent aberrant behavior is detected (by history or urine toxicology), do not abruptly discontinue the patient’s medication(s). Inform the patient of your concern, taper medication, and refer the patient to addiction treatment. Abrupt discontinuation of an opioid or benzodiazepine can lead to significant harm.^1,14

CORRESPONDENCE
John Hayes, DO, Department of Family and Community Medicine, Medical College of Wisconsin, 1121 E North Avenue, Milwaukee, WI, 53212; [email protected]

An estimated 20 million patients in the United States have a substance use disorder (SUD), with hundreds of millions of prescriptions for controlled substances written annually. Consequently, urine drug screening (UDS) has become widely utilized to evaluate and treat patients with an SUD or on chronic opioid or benzodiazepine therapy.¹

Used appropriately, UDS can be a valuable tool; there is ample evidence, however, that it has been misused, by some physicians, to stigmatize patients who use drugs of abuse,² profile patients racially,² profit from excessive testing,³ and inappropriately discontinue treatment.⁴

A patient-centered approach. We have extensive clinical experience in the use and interpretation of urine toxicology, serving as clinical leads in busy family medicine residency practices that care for patients with SUDs, and are often consulted regarding patients on chronic opioid or benzodiazepine therapy. We have encountered countless situations in which the correct interpretation of UDS is critical to providing care.

Over time, and after considerable trial and error, we developed the patient-centered approach to urine toxicology described in this article. We believe that the medical evidence strongly supports our approach to the appropriate use and interpretation of urine toxicology in clinical practice. Our review here is intended as a resource when you consider implementing a UDS protocol or are struggling with the management of unexpected results.

Urine toxicology for therapeutic drug monitoring

Prescribing a controlled substance carries inherent risks, including diversion, nonmedical use, and development of an SUD. Prescribed medications, particularly opioids and benzodiazepines, have been linked to a large increase in overdose deaths over the past decade.⁵ Several strategies have been investigated to mitigate risk (see “How frequently should a patient be tested?,” later in the article).

Clinical judgment—ie, when a physician orders a drug test upon suspecting that a patient is diverting a prescribed drug or has developed a substance use disorder—has been shown to be highly inaccurate.

Clinical judgment—ie, when a physician orders a drug test upon suspecting that a patient is diverting a prescribed drug or has developed an SUD—has been shown to be highly inaccurate. Implicit racial bias might affect the physician’s judgment, leading to changes in testing and test interpretation. For example, Black patients were found to be 10% more likely to have drug screening ordered while being treated with long-term opioid therapy and 2 to 3 times more likely to have their medication discontinued as a result of a marijuana- or cocaine-positive test.²

Other studies have shown that testing patients for “bad behavior,” so to speak—reporting a prescription lost or stolen, consuming more than the prescribed dosage, visiting the office without an appointment, having multiple drug intolerances and allergies, and making frequent telephone calls to the practice—is ineffective.⁶ Patients with these behaviors were slightly more likely to unexpectedly test positive, or negative, on their UDS; however, many patients without suspect behavior also were found to have abnormal toxicology results.⁶ Data do not support therapeutic drug monitoring only of patients selected on the basis of aberrant behavior.⁶

Continue to: Questions and concerns about urine drug screening

Why not just ask the patient? Studies have evaluated whether patient self-reporting of adherence is a feasible alternative to laboratory drug screening. Regrettably, patients have repeatedly been shown to underreport their use of both prescribed and illicit drugs.^7,8

That question leads to another: Why do patients lie to their physician? It is easy to assume malicious intent, but a variety of obstacles might dissuade a patient from being fully truthful with their physician:

• Monetary gain. A small, but real, percentage of medications are diverted by patients for this reason.⁹
• Addiction, pseudo-addiction due to tolerance, and self-medication for psychological symptoms are clinically treatable syndromes that can lead to underreporting of prescribed and nonprescribed drug and alcohol use.
• Shame. Addiction is a highly stigmatized disease, and patients might simply be ashamed to admit that they need treatment: 13% to 38% of patients receiving chronic opioid therapy in a pain management or primary care setting have a clinically diagnosable SUD.^10,11

Is consent needed to test or to share test results? Historically, UDS has been performed on patients without their consent or knowledge.¹² Patients give a urine specimen to their physician for a variety of reasons; it seems easy to “add on” UDS. Evidence is clear, however, that confronting a patient about an unexpected test result can make the clinical outcome worse—often resulting in irreparable damage to the patient–­physician relationship.^12,13 Unless the patient is experiencing a medical emergency, guidelines unanimously recommend obtaining consent prior to testing.^1,5,14

Annual screening is appropriate in low-risk patients; moderate-risk patients should be screened twice a year, and high-risk patients should be screened at least every 4 months.

Federal law requires written permission from the patient for the physician to disclose information about alcohol or substance use, unless the information is expressly needed to provide care during a medical emergency. Substance use is highly stigmatized, and patients might—legitimately—fear that sharing their history could undermine their care.^1,12,14

How frequently should a patient be tested? Experts recommend utilizing a risk-based strategy to determine the frequency of UDS.^1,5,15 Validated risk-assessment questionnaires include:

• Opioid Risk Tool for Opioid Use Disorder (ORT-OUD)^a
• Screener and Opioid Assessment for Patients With Pain–Revised (SOAPP-R)^b
• Diagnosis, Intractability, Risk and Efficacy (DIRE)^c
• Addiction Behaviors Checklist (ABC).^d

Continue to: Each of these tools...

Each of these tools takes less than 5 minutes to administer and can be used by a primary care physician to objectively quantify the risk of prescribing; there is no evidence for the use of 1 of these screeners over the others.¹⁵ It is recommended that you choose a questionnaire that works for you and incorporate the risk assessment into prescribing any high-risk medication.^1,5,15

Once you have completed an initial risk assessment, the frequency of UDS can be based on ongoing assessment that incorporates baseline testing, patient self-reporting, toxicology results, behavioral monitoring, and state database monitoring through a prescription drug monitoring program. Annual screening is appropriate in low-risk patients; moderate-risk patients should be screened twice a year, and high-risk patients should be screened at least every 4 months (FIGURE).¹⁵

Many state and federal agencies, health systems, employers, and insurers mandate the frequency of testing through guidelines or legislation. These regulations often are inconsistent with the newest medical evidence.¹⁵ Consult local guidelines and review the medical evidence and consensus recommendations on UDS.

What are the cost considerations in providing UDS? Insurers have been billed as much as $4000 for definitive chromatography testing (described later).³ This has led to insurance fraud, when drug-testing practices with a financial interest routinely use large and expensive test panels, test too frequently, or unnecessarily send for confirmatory or quantitative analysis of all positive tests.^3,14 Often, insurers refuse to pay for unnecessary testing, leaving patients with significant indebtedness.^3,14 Take time to review the evidence and consensus recommendations on UDS to avoid waste, potential accusations of fraud, and financial burden on your patients.

Urine toxicology for addiction treatment

UDS protocols in addiction settings are often different from those in which a controlled substance is being prescribed.

Continue to: Routine and random testing

Routine and random testing. Two common practices when treating addiction are to perform UDS on all patients, at every visit, or to test randomly.¹ These practices can be problematic, however. Routine testing at every visit can make urine-tampering more likely and is often unnecessary for stable patients. Random testing can reduce the risk of urine-tampering, but it is often difficult for primary care clinics to institute such a protocol. Some clinics have patients provide a urine specimen at every visit and then only send tests to the lab based on randomization.¹

Contingency management—a behavioral intervention in which a patient is rewarded, or their performance is reinforced, when they display evidence of positive change—is the most effective strategy used in addiction medicine to determine the frequency of patient visits and UDS.^14,16 High-risk patients with self-reported active substance use or UDS results consistent with substance use, or both, are seen more often; as their addiction behavior diminishes, visits and UDS become less frequent. If addiction behavior increases, the patient is seen more often. Keep in mind that addiction behavior decreases over months of treatment, not immediately upon initiation.^14,17 For contingency management to be successful, patient-centered interviewing and UDS will need to be employed frequently as the patient works toward meaningful change.¹⁴

The technology of urine drug screening

Two general techniques are used for UDS: immunoassay and chromatography. Each plays an important role in clinical practice; physicians must therefore maintain a basic understanding of the mechanism of each technique and their comparable advantages and disadvantages. Such an understanding allows for (1) matching the appropriate technique to the individual clinical scenario and (2) correctly interpreting results.

Immunoassay technology is used for point-of-care and rapid laboratory UDS, using antibodies to detect the drug or drug metabolite of interest. Antibodies utilized in immunoassays are designed to selectively bind a specific antigen—ie, a unique chemical structure within the drug of choice. Once bound, the antigen–antibody complex can be exploited for detection through various methods.

Chromatography–mass ­spectrometry is considered the gold standard for UDS, yielding confirmatory results. This is a 2-step process: Chromatography separates components within a specimen; mass spectrometry then identifies those components. Most laboratories employ liquid, rather than gas, chromatography. The specificity of the liquid chromatography–mass spectrometry method is such that a false-positive result is, essentially, impossible.¹⁸

Continue to: How is the appropriate tests elected for urine drug screening?

Variables that influence your choice of the proper test method include the clinical question at hand; cost; the urgency of obtaining results; and the stakes in that decision (ie, will the results be used to simply change the dosage of a medication or, of greater consequence, to determine fitness for employment or inform criminal justice decisions?). Each method of UDS has advantages that can be utilized and disadvantages that must be considered to obtain an accurate and useful result.

Immunoassay provides rapid results, is relatively easy to perform, and is, comparatively, inexpensive.^1,14 The speed of results makes this method particularly useful in settings such as the emergency department, where rapid results are crucial. Ease of use makes immunoassay ideal for the office, where non-laboratory staff can be trained to properly administer the test.

A major disadvantage of immunoassay technology, however, is interference resulting in both false-positive and false-negative results, which is discussed in detail in the next section. Immunoassay should be considered a screening test that yields presumptive results.

Liquid chromatography–mass spectrometry is exquisitely specific and provides confirmatory test results—major advantages of the method. However, specificity comes at a price: significantly increased cost and longer wait time for results (typically days, if specimens are sent out to a laboratory). These barriers can make it impractical to employ this method in routine practice.

Interpretation of results: Not so fast

Interpreting UDS results is not as simple as noting a positive or negative result. Physicians must understand the concept of interference, so that results can be appropriately interpreted and confirmed. This is crucial when results influence clinical decisions; inappropriate action, taken on the basis of presumptive results, can have severe consequences for the patient–provider relationship and the treatment plan.^1,14

Continue to: Interference falls into 2 categories...

Interference falls into 2 categories: variables inherent in the testing process and patient variables.

Obtain consent prior to performing urine drug screening, even if you are already collecting a specimen for other testing.

Antibody cross-reactivity. A major disadvantage of immunoassay technology is interference that results in false-positive and false-negative results.^19,20 The source of this interference is antibody cross-­reactivity—the degree to which an antibody binds to structurally similar compounds. Antibody–­antigen interactions are incredibly complex; although assay antibodies are engineered to specifically detect a drug class of interest, reactivity with other, structurally similar compounds is unavoidable.

Nevertheless, cross-reactivity is a useful phenomenon that allows broad testing for multiple drugs within a class. For example, most point-of-care tests for benzodiazepines reliably detect diazepam and chlordiazepoxide. Likewise, opiate tests reliably detect natural opiates, such as morphine and codeine. Cross-reactivity is not limitless, however; most benzodiazepine immunoassays have poor reactivity to clonazepam and lorazepam, making it possible that a patient taking clonazepam tests negative for benzodiazepine on an immunoassay.^14,20 Similarly, standard opioid tests have only moderate cross-reactivity for semisynthetic opioids, such as hydrocodone and hydromorphone; poor cross-r­eactivity for oxycodone and oxymorphone; and essentially no cross-­reactivity for full synthetics, such as fentanyl and methadone.¹⁴

It is the responsibility of the ordering physician to understand cross-reactivity to various drugs within a testing class.

Routine urine drug screening at every visit can make urine tampering more likely and is often unnecessary for stable patients.

Whereas weak cross-reactivity to drugs within a class can be a source of false-negative results, cross-reactivity to drugs outside the class of interest is a source of false-positive results. An extensive review of drugs that cause false-positive immunoassay screening tests is outside the scope of this article; commonly prescribed medications implicated in false-positive results are listed in TABLE 1.¹⁹

Continue to: In general...

In general, amphetamine immunoassays produce frequent false-positive results, whereas cocaine and cannabinoid assays are more specific.^1,18 Common over-the-counter medications, including nonsteroidal anti-inflammatory drugs, decongestants, and antacids, can yield false-positive results, highlighting the need to obtain a comprehensive medication list from patients, including over-the-counter and herbal medications, before ordering UDS. Because of the complexity of cross-reactivity, it might not be possible to identify the source of a false-positive result.¹⁴

Patient variables. Intentional effort to skew results is another source of interference. The frequency of this effort varies by setting and the potential consequences of results—eg, employment testing or substance use treatment—and a range of attempts have been reported in the literature.^21,22 Common practices are dilution, adulteration, and substitution.^20,23

• Dilution lowers the concentration of the drug of interest below the detection limit of the assay by directly adding water to the urine specimen, drinking copious amounts of fluid, taking a diuretic, or a combination of these practices.
• Adulteration involves adding a substance to urine that interferes with the testing mechanism: for example, bleach, household cleaners, eye drops, and even commercially available products expressly marketed to interfere with UDS.²⁴
• Substitution involves providing urine or a urine-like substance for testing that did not originate from the patient.

Methods to minimize patient-related interference include observed collection and specimen validity testing for pH, creatinine, and adulterants (TABLE 2).^1,15 Efforts to detect patient interference must be balanced against concerns about privacy, personnel resources, and the cost of expanded testing.^14,19,20

Additional aspects inherent to the testing process, such as cutoff concentrations and detection windows, can lead to interference. Laboratories must set reporting cutoffs, and specimens with a drug concentration present but below the cutoff value are reported as a negative result. Detection windows are complex and are influenced by inherent properties of the drug, including metabolic pathway and route and frequency of use.¹ A given patient might well be using a substance, but if the specimen was obtained outside the detection window, a false-negative result might be reported (TABLE 3^1,23).

Managing test results

Appropriate management of UDS results is built on the foundation of understanding the testing mechanism, selecting the correct test, and properly interpreting results. Drug testing is, ultimately, a therapeutic tool used to monitor treatment, provide reinforcement, and explore substance use behavior; results of testing should be employed to achieve those objectives.^1,4,14 A negative or expected UDS result can be utilized as positive reinforcement for a patient who is adherent to the treatment plan—much the way objective weight loss in an obese patient can provide encouragement to continue lifestyle changes.

Continue to: Test results should be presented...

Test results should be presented in an objective, nonconfrontational, and compassionate manner, not with stigmatizing language, such as “clean” or “dirty.”^1,13,14 Using stigmatizing terms such as “substance abuser” instead of “person with a substance use disorder” has been shown, even among highly trained health care professionals, to have a negative effect on patient care.¹³

A given patient might well be using a substance, but if the specimen was obtained outside the detection window, a false-negative result might be reported.

Inevitably, you will encounter an unexpected result, and therefore must develop a rational, systematic, and compassionate management approach. “Unexpected result” is a broad term that includes results that conflict with

• a patient’s self-report
• your understanding of what the patient is taking (using)
• prescribed medications
• a patient’s typical substance use pattern.

When faced with an unexpected test result, first, ensure that the result in question is reliable. If a screening test yields an unanticipated finding—especially if it conflicts with the patient’s self-reporting—make every effort to seek confirmation if you are going to be making a significant clinical decision because of the result.^1,14

Second, use your understanding of interference to consider the result in a broader context. If confirmatory results are inconsistent with a patient’s self-report, discuss whether there has been a break in the ­ph­ysician–patient relationship and emphasize that recurrent use or failure to adhere to a treatment plan has clear consequences.^1,14 Modify the treatment plan to address the inconsistent finding by escalating care, adjusting medications, and connecting the patient to additional resources.

Third, keep in mind that a positive urine test is not diagnostic of an SUD. Occasional drug use is extremely common¹⁷ and should not categorically lead to a change in the treatment plan. Addiction is, fundamentally, a disease of disordered reward, motivation, and behavior that is defined by the consequences of substance use, not substance use per se,²⁵ and an SUD diagnosis is complex, based on clinical history, physical examination, and laboratory testing. Similarly, a negative UDS result does not rule out an SUD.^4,10

Continue to: Fourth, patient dismissal...

Fourth, patient dismissal is rarely an appropriate initial response to UDS results. Regrettably, some physicians misinterpret urine toxicology results and inappropriately discharge patients on that basis.

In general, amphetamine immunoassays produce frequent falsepositive results, whereas cocaine and cannabinoid assays are more specific.

The Centers for Disease Control and Prevention guideline for prescribing opioids has increased utilization of UDS in primary care settings but does not provide the necessary education on proper use of the tool, which has resulted in a rise in misinterpretation and inappropriate discharge.^13,26

If recurrent aberrant behavior is detected (by history or urine toxicology), do not abruptly discontinue the patient’s medication(s). Inform the patient of your concern, taper medication, and refer the patient to addiction treatment. Abrupt discontinuation of an opioid or benzodiazepine can lead to significant harm.^1,14

CORRESPONDENCE
John Hayes, DO, Department of Family and Community Medicine, Medical College of Wisconsin, 1121 E North Avenue, Milwaukee, WI, 53212; [email protected]

An estimated 20 million patients in the United States have a substance use disorder (SUD), with hundreds of millions of prescriptions for controlled substances written annually. Consequently, urine drug screening (UDS) has become widely utilized to evaluate and treat patients with an SUD or on chronic opioid or benzodiazepine therapy.¹

Used appropriately, UDS can be a valuable tool; there is ample evidence, however, that it has been misused, by some physicians, to stigmatize patients who use drugs of abuse,² profile patients racially,² profit from excessive testing,³ and inappropriately discontinue treatment.⁴

A patient-centered approach. We have extensive clinical experience in the use and interpretation of urine toxicology, serving as clinical leads in busy family medicine residency practices that care for patients with SUDs, and are often consulted regarding patients on chronic opioid or benzodiazepine therapy. We have encountered countless situations in which the correct interpretation of UDS is critical to providing care.

Over time, and after considerable trial and error, we developed the patient-centered approach to urine toxicology described in this article. We believe that the medical evidence strongly supports our approach to the appropriate use and interpretation of urine toxicology in clinical practice. Our review here is intended as a resource when you consider implementing a UDS protocol or are struggling with the management of unexpected results.

Urine toxicology for therapeutic drug monitoring

Prescribing a controlled substance carries inherent risks, including diversion, nonmedical use, and development of an SUD. Prescribed medications, particularly opioids and benzodiazepines, have been linked to a large increase in overdose deaths over the past decade.⁵ Several strategies have been investigated to mitigate risk (see “How frequently should a patient be tested?,” later in the article).

Clinical judgment—ie, when a physician orders a drug test upon suspecting that a patient is diverting a prescribed drug or has developed a substance use disorder—has been shown to be highly inaccurate.

Clinical judgment—ie, when a physician orders a drug test upon suspecting that a patient is diverting a prescribed drug or has developed an SUD—has been shown to be highly inaccurate. Implicit racial bias might affect the physician’s judgment, leading to changes in testing and test interpretation. For example, Black patients were found to be 10% more likely to have drug screening ordered while being treated with long-term opioid therapy and 2 to 3 times more likely to have their medication discontinued as a result of a marijuana- or cocaine-positive test.²

Other studies have shown that testing patients for “bad behavior,” so to speak—reporting a prescription lost or stolen, consuming more than the prescribed dosage, visiting the office without an appointment, having multiple drug intolerances and allergies, and making frequent telephone calls to the practice—is ineffective.⁶ Patients with these behaviors were slightly more likely to unexpectedly test positive, or negative, on their UDS; however, many patients without suspect behavior also were found to have abnormal toxicology results.⁶ Data do not support therapeutic drug monitoring only of patients selected on the basis of aberrant behavior.⁶

Continue to: Questions and concerns about urine drug screening

Why not just ask the patient? Studies have evaluated whether patient self-reporting of adherence is a feasible alternative to laboratory drug screening. Regrettably, patients have repeatedly been shown to underreport their use of both prescribed and illicit drugs.^7,8

That question leads to another: Why do patients lie to their physician? It is easy to assume malicious intent, but a variety of obstacles might dissuade a patient from being fully truthful with their physician:

• Monetary gain. A small, but real, percentage of medications are diverted by patients for this reason.⁹
• Addiction, pseudo-addiction due to tolerance, and self-medication for psychological symptoms are clinically treatable syndromes that can lead to underreporting of prescribed and nonprescribed drug and alcohol use.
• Shame. Addiction is a highly stigmatized disease, and patients might simply be ashamed to admit that they need treatment: 13% to 38% of patients receiving chronic opioid therapy in a pain management or primary care setting have a clinically diagnosable SUD.^10,11

Is consent needed to test or to share test results? Historically, UDS has been performed on patients without their consent or knowledge.¹² Patients give a urine specimen to their physician for a variety of reasons; it seems easy to “add on” UDS. Evidence is clear, however, that confronting a patient about an unexpected test result can make the clinical outcome worse—often resulting in irreparable damage to the patient–­physician relationship.^12,13 Unless the patient is experiencing a medical emergency, guidelines unanimously recommend obtaining consent prior to testing.^1,5,14

Annual screening is appropriate in low-risk patients; moderate-risk patients should be screened twice a year, and high-risk patients should be screened at least every 4 months.

Federal law requires written permission from the patient for the physician to disclose information about alcohol or substance use, unless the information is expressly needed to provide care during a medical emergency. Substance use is highly stigmatized, and patients might—legitimately—fear that sharing their history could undermine their care.^1,12,14

How frequently should a patient be tested? Experts recommend utilizing a risk-based strategy to determine the frequency of UDS.^1,5,15 Validated risk-assessment questionnaires include:

• Opioid Risk Tool for Opioid Use Disorder (ORT-OUD)^a
• Screener and Opioid Assessment for Patients With Pain–Revised (SOAPP-R)^b
• Diagnosis, Intractability, Risk and Efficacy (DIRE)^c
• Addiction Behaviors Checklist (ABC).^d

Continue to: Each of these tools...

Each of these tools takes less than 5 minutes to administer and can be used by a primary care physician to objectively quantify the risk of prescribing; there is no evidence for the use of 1 of these screeners over the others.¹⁵ It is recommended that you choose a questionnaire that works for you and incorporate the risk assessment into prescribing any high-risk medication.^1,5,15

Once you have completed an initial risk assessment, the frequency of UDS can be based on ongoing assessment that incorporates baseline testing, patient self-reporting, toxicology results, behavioral monitoring, and state database monitoring through a prescription drug monitoring program. Annual screening is appropriate in low-risk patients; moderate-risk patients should be screened twice a year, and high-risk patients should be screened at least every 4 months (FIGURE).¹⁵

Many state and federal agencies, health systems, employers, and insurers mandate the frequency of testing through guidelines or legislation. These regulations often are inconsistent with the newest medical evidence.¹⁵ Consult local guidelines and review the medical evidence and consensus recommendations on UDS.

What are the cost considerations in providing UDS? Insurers have been billed as much as $4000 for definitive chromatography testing (described later).³ This has led to insurance fraud, when drug-testing practices with a financial interest routinely use large and expensive test panels, test too frequently, or unnecessarily send for confirmatory or quantitative analysis of all positive tests.^3,14 Often, insurers refuse to pay for unnecessary testing, leaving patients with significant indebtedness.^3,14 Take time to review the evidence and consensus recommendations on UDS to avoid waste, potential accusations of fraud, and financial burden on your patients.

Urine toxicology for addiction treatment

UDS protocols in addiction settings are often different from those in which a controlled substance is being prescribed.

Continue to: Routine and random testing

Routine and random testing. Two common practices when treating addiction are to perform UDS on all patients, at every visit, or to test randomly.¹ These practices can be problematic, however. Routine testing at every visit can make urine-tampering more likely and is often unnecessary for stable patients. Random testing can reduce the risk of urine-tampering, but it is often difficult for primary care clinics to institute such a protocol. Some clinics have patients provide a urine specimen at every visit and then only send tests to the lab based on randomization.¹

Contingency management—a behavioral intervention in which a patient is rewarded, or their performance is reinforced, when they display evidence of positive change—is the most effective strategy used in addiction medicine to determine the frequency of patient visits and UDS.^14,16 High-risk patients with self-reported active substance use or UDS results consistent with substance use, or both, are seen more often; as their addiction behavior diminishes, visits and UDS become less frequent. If addiction behavior increases, the patient is seen more often. Keep in mind that addiction behavior decreases over months of treatment, not immediately upon initiation.^14,17 For contingency management to be successful, patient-centered interviewing and UDS will need to be employed frequently as the patient works toward meaningful change.¹⁴

The technology of urine drug screening

Two general techniques are used for UDS: immunoassay and chromatography. Each plays an important role in clinical practice; physicians must therefore maintain a basic understanding of the mechanism of each technique and their comparable advantages and disadvantages. Such an understanding allows for (1) matching the appropriate technique to the individual clinical scenario and (2) correctly interpreting results.

Immunoassay technology is used for point-of-care and rapid laboratory UDS, using antibodies to detect the drug or drug metabolite of interest. Antibodies utilized in immunoassays are designed to selectively bind a specific antigen—ie, a unique chemical structure within the drug of choice. Once bound, the antigen–antibody complex can be exploited for detection through various methods.

Chromatography–mass ­spectrometry is considered the gold standard for UDS, yielding confirmatory results. This is a 2-step process: Chromatography separates components within a specimen; mass spectrometry then identifies those components. Most laboratories employ liquid, rather than gas, chromatography. The specificity of the liquid chromatography–mass spectrometry method is such that a false-positive result is, essentially, impossible.¹⁸

Continue to: How is the appropriate tests elected for urine drug screening?

Variables that influence your choice of the proper test method include the clinical question at hand; cost; the urgency of obtaining results; and the stakes in that decision (ie, will the results be used to simply change the dosage of a medication or, of greater consequence, to determine fitness for employment or inform criminal justice decisions?). Each method of UDS has advantages that can be utilized and disadvantages that must be considered to obtain an accurate and useful result.

Immunoassay provides rapid results, is relatively easy to perform, and is, comparatively, inexpensive.^1,14 The speed of results makes this method particularly useful in settings such as the emergency department, where rapid results are crucial. Ease of use makes immunoassay ideal for the office, where non-laboratory staff can be trained to properly administer the test.

A major disadvantage of immunoassay technology, however, is interference resulting in both false-positive and false-negative results, which is discussed in detail in the next section. Immunoassay should be considered a screening test that yields presumptive results.

Liquid chromatography–mass spectrometry is exquisitely specific and provides confirmatory test results—major advantages of the method. However, specificity comes at a price: significantly increased cost and longer wait time for results (typically days, if specimens are sent out to a laboratory). These barriers can make it impractical to employ this method in routine practice.

Interpretation of results: Not so fast

Interpreting UDS results is not as simple as noting a positive or negative result. Physicians must understand the concept of interference, so that results can be appropriately interpreted and confirmed. This is crucial when results influence clinical decisions; inappropriate action, taken on the basis of presumptive results, can have severe consequences for the patient–provider relationship and the treatment plan.^1,14

Continue to: Interference falls into 2 categories...

Interference falls into 2 categories: variables inherent in the testing process and patient variables.

Obtain consent prior to performing urine drug screening, even if you are already collecting a specimen for other testing.

Antibody cross-reactivity. A major disadvantage of immunoassay technology is interference that results in false-positive and false-negative results.^19,20 The source of this interference is antibody cross-­reactivity—the degree to which an antibody binds to structurally similar compounds. Antibody–­antigen interactions are incredibly complex; although assay antibodies are engineered to specifically detect a drug class of interest, reactivity with other, structurally similar compounds is unavoidable.

Nevertheless, cross-reactivity is a useful phenomenon that allows broad testing for multiple drugs within a class. For example, most point-of-care tests for benzodiazepines reliably detect diazepam and chlordiazepoxide. Likewise, opiate tests reliably detect natural opiates, such as morphine and codeine. Cross-reactivity is not limitless, however; most benzodiazepine immunoassays have poor reactivity to clonazepam and lorazepam, making it possible that a patient taking clonazepam tests negative for benzodiazepine on an immunoassay.^14,20 Similarly, standard opioid tests have only moderate cross-reactivity for semisynthetic opioids, such as hydrocodone and hydromorphone; poor cross-r­eactivity for oxycodone and oxymorphone; and essentially no cross-­reactivity for full synthetics, such as fentanyl and methadone.¹⁴

It is the responsibility of the ordering physician to understand cross-reactivity to various drugs within a testing class.

Routine urine drug screening at every visit can make urine tampering more likely and is often unnecessary for stable patients.

Whereas weak cross-reactivity to drugs within a class can be a source of false-negative results, cross-reactivity to drugs outside the class of interest is a source of false-positive results. An extensive review of drugs that cause false-positive immunoassay screening tests is outside the scope of this article; commonly prescribed medications implicated in false-positive results are listed in TABLE 1.¹⁹

Continue to: In general...

In general, amphetamine immunoassays produce frequent false-positive results, whereas cocaine and cannabinoid assays are more specific.^1,18 Common over-the-counter medications, including nonsteroidal anti-inflammatory drugs, decongestants, and antacids, can yield false-positive results, highlighting the need to obtain a comprehensive medication list from patients, including over-the-counter and herbal medications, before ordering UDS. Because of the complexity of cross-reactivity, it might not be possible to identify the source of a false-positive result.¹⁴

Patient variables. Intentional effort to skew results is another source of interference. The frequency of this effort varies by setting and the potential consequences of results—eg, employment testing or substance use treatment—and a range of attempts have been reported in the literature.^21,22 Common practices are dilution, adulteration, and substitution.^20,23

• Dilution lowers the concentration of the drug of interest below the detection limit of the assay by directly adding water to the urine specimen, drinking copious amounts of fluid, taking a diuretic, or a combination of these practices.
• Adulteration involves adding a substance to urine that interferes with the testing mechanism: for example, bleach, household cleaners, eye drops, and even commercially available products expressly marketed to interfere with UDS.²⁴
• Substitution involves providing urine or a urine-like substance for testing that did not originate from the patient.

Methods to minimize patient-related interference include observed collection and specimen validity testing for pH, creatinine, and adulterants (TABLE 2).^1,15 Efforts to detect patient interference must be balanced against concerns about privacy, personnel resources, and the cost of expanded testing.^14,19,20

Additional aspects inherent to the testing process, such as cutoff concentrations and detection windows, can lead to interference. Laboratories must set reporting cutoffs, and specimens with a drug concentration present but below the cutoff value are reported as a negative result. Detection windows are complex and are influenced by inherent properties of the drug, including metabolic pathway and route and frequency of use.¹ A given patient might well be using a substance, but if the specimen was obtained outside the detection window, a false-negative result might be reported (TABLE 3^1,23).

Managing test results

Appropriate management of UDS results is built on the foundation of understanding the testing mechanism, selecting the correct test, and properly interpreting results. Drug testing is, ultimately, a therapeutic tool used to monitor treatment, provide reinforcement, and explore substance use behavior; results of testing should be employed to achieve those objectives.^1,4,14 A negative or expected UDS result can be utilized as positive reinforcement for a patient who is adherent to the treatment plan—much the way objective weight loss in an obese patient can provide encouragement to continue lifestyle changes.

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