Andy J. Chien, MD

Even with recent pharmacologic treatment advances, narrowband UVB (NB-UVB) phototherapy remains a versatile, safe, and efficacious adjunctive or exclusive treatment for multiple dermatologic conditions, including psoriasis and atopic dermatitis. ^1-9 Some providers choose NB-UVB phototherapy as a first-line treatment for older adult patients who frequently use multiple treatment modalities for more than 1 health condition. Older adults with atopic dermatitis and psoriasis are at higher risk for comorbidities such as autoimmune disorders, diabetes mellitus, dyslipidemia, sleep disorders, neuropsychiatric disorders, and cardiovascular disease that can complicate treatment compared with their peers without these dermatologic diagnoses. ^10-12 Polypharmacy (ie, the use of 5 or more daily medications), frequently associated with these conditions, contributes to prescribers pursuing NB-UVB phototherapy as a nonpharmacologic treatment, but some providers wonder if it is as effective and safe for their older patients compared with younger patients.

In a prior study, Matthews et al¹³ reported that 96% (50/52) of patients older than 65 years achieved medium to high levels of clearance with NB-UVB phototherapy. Nonetheless, 2 other findings in this study related to the number of treatments required to achieve clearance (ie, clearance rates) and erythema rates prompted further investigation. The first finding was higher-than-expected clearance rates. Older adults had a clearance rate with a mean of 33 treatments compared to prior studies featuring mean clearance rates of 20 to 28 treatments.^7,8,14-16 This finding resembled a study in the United Kingdom¹⁷ with a median clearance rate in older adults of 30 treatments. In contrast, the median clearance rate from a study in Turkey¹⁸ was 42 treatments in older adults. We hypothesized that more photosensitizing medications used in older vs younger adults prompted more dose adjustments with NB-UVB phototherapy to avoid burning (ie, erythema) at baseline and throughout the treatment course. These dose adjustments may have increased the overall clearance rates. If true, we predicted that younger adults treated with the same protocol would have cleared more quickly, either because of age-related differences or because they likely had fewer comorbidities and therefore fewer medications.

The second finding from Matthews et al¹³ that warranted further investigation was a higher erythema rate compared to the older adult study from the United Kingdom.¹⁷ We hypothesized that potentially greater use of photosensitizing medications in the United States could explain the higher erythema rates. Although medication-induced photosensitivity is less likely with NB-UVB phototherapy than with UVA, certain medications can cause UVB photosensitivity, including thiazides, quinidine, calcium channel antagonists, phenothiazines, and nonsteroidal anti-inflammatory drugs.^8,19,20 Therefore, photosensitizing medication use either at baseline or during a course of NB-UVB phototherapy could increase the risk for erythema. Age-related skin changes also have been considered as a potential cause for erythema. One study found that the skin of older patients was more sensitive than younger patients, resulting in a lower minimal erythema dose (MED)¹⁴—the lowest UV dose that results in erythema.²¹ Others, however, found similar MEDs across age groups, but older adults experienced more intense erythema in the late phase of NB-UVB treatment.^22,23 Such conflicting findings indicate that questions remain regarding the risk for erythema in older patients and if photosensitizing medications are responsible for an increased risk.

This retrospective study aimed to determine if NB-UVB phototherapy is equally effective in both older and younger adults treated with the same protocol; to examine the association between the use of photosensitizing medications and clearance rates in both older and younger adults; and to examine the association between the use of photosensitizing medications and erythema rates in older vs younger adults.

Methods

Study Design and Patients—This retrospective cohort study used billing records to identify patients who received NB-UVB phototherapy at 3 different clinical sites within a large US health care system in Washington (Group Health Cooperative, now Kaiser Permanente Washington), serving more than 600,000 patients between January 1, 2012, and December 31, 2016. The institutional review board of Kaiser Permanente Washington Health Research Institute approved this study (IRB 1498087-4). Younger adults were classified as those 64 years or younger and older adults as those 65 years and older at the start of their phototherapy regimen. A power analysis determined that the optimal sample size for this study was 250 patients.

Individuals were excluded if they had fewer than 6 phototherapy treatments; a diagnosis of vitiligo, photosensitivity dermatitis, morphea, or pityriasis rubra pilaris; and/or treatment of the hands or feet only.

Phototherapy Protocol—Using a 48-lamp NB-UVB unit, trained phototherapy nurses provided all treatments following standardized treatment protocols¹³ based on previously published phototherapy guidelines.²⁴ Nurses determined each patient’s disease clearance level using a 3-point clearance scale (high, medium, low).¹³ Each patient’s starting dose was determined based on the estimated MED for their skin phototype. If the patient was using photosensitizing medications, the protocol indicated a need for a decreased starting dose—down 25% to 50%—depending on the presumed level of photosensitivity. All clinical sites used the same protocol, but decisions about adjustments within this range were made by individual registered nurses and dermatologists, which could lead to variability across sites. Protocols also directed nurses to query patients about specific treatment responses, including erythema, tenderness, or itching; how their condition was responding; use of photosensitizing medications; missed treatments; and placement of shielding. Doses were adjusted accordingly.

Statistical Analysis—Data were analyzed using Stata statistical software (StataCorp LLC). Univariate analyses were used to examine the data and identify outliers, bad values, and missing data, as well as to calculate descriptive statistics. Pearson χ² and Fisher exact statistics were used to calculate differences in categorical variables. Linear multivariate regression models and logistic multivariate models were used to examine statistical relationships between variables. Statistical significance was defined as P≤.05.

Results

Patient Characteristics—Medical records were reviewed for 172 patients who received phototherapy between 2012 and 2016. Patients ranged in age from 23 to 91 years, with 102 patients 64 years and younger and 70 patients 65 years and older. Tables 1 and 2 outline the patient characteristics and conditions treated.

Phototherapy Effectiveness—Narrowband UVB phototherapy was found to be equally effective in older vs younger adults, with 82.9% of older adults (n=58) achieving a high level of clearance vs 80.4% (n=82) of younger adults, and 5.7% (n=4) of older adults achieved a medium level of clearance vs 10% (n=10) of younger adults (Table 3). Although older adults had slightly faster clearance rates on average (34.6 vs 37.2 treatments), these differences were not significant.

Photosensitizing Medications, Clearance Levels, and Clearance Rates—There was no significant association between clearance levels and number of photosensitizing medications in either younger (Figure 1) or older (Figure 2) adults. There was a wide range of clearance rates in both groups (Table 3), but no relationship was identified between clearance rates and photosensitizing medications or age (Figure 3). Clinic C had higher overall clearance rates for both age groups compared to the other clinics (Figure 4), but the clearance levels were still equivalent. No consistent pattern emerged indicating that age was a factor for the slower clearance at this site, and no relationship was identified between taking photosensitizing medications and clearance levels (Fisher exact test, P=.467) or clearance rates (t[149]=0.75; P=.45).

Frequency of Treatments and Clearance Rates—Older adults more consistently completed the recommended frequency of treatments—3 times weekly—compared to younger adults (74.3% vs 58.5%). However, all patients who completed 3 treatments per week required a similar number of treatments to clear (older adults, mean [SD]: 35.7 [21.6]; younger adults, mean [SD]: 34.7 [19.0]; P=.85). Among patients completing 2 or fewer treatments per week, older adults required a mean (SD) of only 31 (9.0) treatments to clear vs 41.5 (21.3) treatments to clear for younger adults, but the difference was not statistically significant (P=.08). However, even those with suboptimal frequency ultimately achieved similar clearance levels.

Photosensitizing Medications and Erythema Rates—Many patients in both age groups took medications that listed photosensitivity as a potential side effect (77.1% of older adults and 60.8% of younger adults). Of them, most patients took only 1 or 2 photosensitizing medications. However, significantly more older patients took 3 or more photosensitizing medications (28.6% vs 12.7%; P=.01)(Table 3). Asymptomatic (grade 1) erythema was unrelated to medication use and quite common in all adults (48.6% of older adults and 60.8% of younger adults). Most patients had only a few episodes of grade 1 erythema (mean [SD], 1.2 [2.9] in older adults and 1.6 [2.2] in younger adults). More older adults had grade 2 erythema (28.6%) compared to younger adults (17.6%). Patients using 3 or more photosensitizing medications were twice as likely to experience grade 2 erythema. Grades 3 and 4 erythema were extremely rare; none of the patients stopped phototherapy because they experienced erythema.

Overall, phototherapy nurses adjusted the starting dose according to the phototype-based protocol an average of 69% of the time for patients on medications with photosensitivity listed as a potential side effect. However, the frequency depended significantly on the clinic (clinic A, 24%; clinic B, 92%; clinic C, 87%)(P≤.001). Nurses across all clinics consistently decreased the treatment dose when patients reported starting new photosensitizing medications. Patients with adjusted starting doses had slightly but not significantly higher clearance rates compared to those without (mean, 37.8 vs 35.5; t(104)=0.58; P=.56).

Comment

Comparisons to Prior Studies—This study confirmed that phototherapy is equally effective for older and younger adults, with approximately 90% reaching medium to high clearance levels with approximately 35 treatments in both groups. Prior studies of all age groups found that patients typically cleared with an average of 20 to 28 treatments.^7,8,14-16 In contrast, the findings in older adults from this study were similar to the older adult study from the United Kingdom that reported a 91% clear/near clear rate with an average of 30 treatments.¹⁷ The clearance level also was similar to the older adult study in Turkey¹⁸ that reported 73.7% (70/95) of patients with psoriasis achieved a minimum psoriasis area severity index of 75, indicating 75% improvement from baseline.

Impact of Photosensitizing Medications on Clearance—Photosensitizing medications and treatment frequency were 2 factors that might explain the slower clearance rates in younger adults. In this study, both groups of patients used similar numbers of photosensitizing medications, but more older adults were taking 3 or more medications (Table 3). We found no statistically significant relationship between taking photosensitizing medications and either the clearance rates or the level of clearance achieved in either age group.

Impact of Treatment Frequency—Weekly treatment frequency also was examined. One prior study demonstrated that treatments 3 times weekly led to a faster clearance time and higher clearance levels compared with twice-weekly treatment.⁷ When patients completed treatments twice weekly, it took an average of 1.5 times more days to clear, which impacted cost and clinical resource availability. The patients ranged in age from 17 to 80 years, but outcomes in older patients were not described separately.⁷ Interestingly, our study seemed to find a difference between age groups when the impact of treatment frequency was examined. Older adults completed nearly 4 fewer mean treatments to clear when treating less often, with more than 80% achieving high levels of clearance, whereas the younger adults required almost 7 more treatments to clear when they came in less frequently, with approximately 80% achieving a high level of clearance. As a result, our study found that in both age groups, slowing the treatment frequency extended the treatment time to clearance—more for the younger adults than the older adults—but did not significantly change the percentage of individuals reaching full clearance in either group.

Erythema Rates—There was no association between photosensitizing medications and erythema rates except when patients were taking at least 3 medications. Most medications that listed photosensitivity as a possible side effect did not specify their relevant range of UV radiation; therefore, all such medications were examined during this analysis. Prior research has shown UVB range photosensitizing medications include thiazides, quinidine, calcium channel antagonists, phenothiazines, and nonsteroidal anti-inflammatory drugs.¹⁹ A sensitivity analysis that focused only on these medications found no association between them and any particular grade of erythema. However, patients taking 3 or more of any medications listing photosensitivity as a side effect had an increased risk for grade 2 erythema.

Erythema rates in this study were consistent with a 2013 systematic review that reported 57% of patients with asymptomatic grade 1 erythema.²⁵ In the 2 other comparative older adult studies, erythema rates varied widely: 35% in a study from Turkey¹⁸compared to only1.89% in a study from the United Kingdom.¹⁷

The starting dose for NB-UVB may drive erythema rates. The current study’s protocols were based on an estimated MED that is subjectively determined by the dermatology provider’s assessment of the patient’s skin sensitivity via examination and questions to the patient about their response to environmental sun exposure (ie, burning and tanning)²⁶ and is frequently used to determine the starting dose and subsequent dose escalation. Certain medications have been found to increase photosensitivity and erythema,²⁰ which can change an individual’s MED. If photosensitizing medications are started prior to or during a course of NB-UVB without a pretreatment MED, they might increase the risk for erythema. This study did not identify specific erythema-inducing medications but did find that taking 3 or more photosensitizing medications was associated with increased episodes of grade 2 erythema. Similarly, Harrop et al⁸ found that patients who were taking photosensitizing medications were more likely to have grade 2 or higher erythema, despite baseline MED testing, which is an established safety mechanism to reduce the risk and severity of erythema.^14,20,27 The authors of a recent study of older adults in Taiwan specifically recommended MED testing due to the unpredictable influence of polypharmacy on MED calculations in this population.²⁸ Therefore, this study’s use of an estimated MED in older adults may have influenced the starting dose as well as the incidence and severity of erythemic events. Age-related skin changes likely are ruled out as a consideration for mild erythema by the similarity of grade 1 erythema rates in both older and younger adults. Other studies have identified differences between the age groups, where older patients experienced more intense erythema in the late phase of UVB treatments.^22,23 This phenomenon could increase the risk for a grade 2 erythema, which may correspond with this study’s findings.

Other potential causes of erythema were ruled out during our study, including erythema related to missed treatments and shielding mishaps. Other factors, however, may impact the level of sensitivity each patient has to phototherapy, including genetics, epigenetics, and cumulative sun damage. With NB-UVB, near-erythemogenic doses are optimal to achieve effective treatments but require a delicate balance to achieve, which may be more problematic for older adults, especially those taking several medications.

Study Limitations—Our study design made it difficult to draw conclusions about rarer dermatologic conditions. Some patients received treatments over years that were not included in the study period. Finally, power calculations suggested that our actual sample size was too small, with approximately one-third of the required sample missing.

Practical Implications—The goals of phototherapy are to achieve a high level of disease clearance with the fewest number of treatments possible and minimal side effects. Skin phototype–driven standardized doses based on estimated MED may be conservatively low to minimize the risk of side effects (eg, erythema), which could slow the treatment progression. Thus, basing the starting dose on individual MED assessments may improve clearance rates. This study also confirmed that phototherapy is safe with minimal erythema in adults of all ages. The erythema episodes that patients experienced were few and mild, but because of greater rates of grade 2 erythema in patients on 3 or more photosensitizing medications, consideration of MED testing in both age groups might optimize doses at baseline and prompt caution for subsequent dose titration in this subset of patients.

The extra staff training and patient monitoring required for MED testing likely is to add value and preserve resources if faster clearance rates could be achieved and may warrant further investigation. Phototherapy centers require standardized treatment protocols, diligent well-trained staff, and program monitoring to ensure consistent care to all patients. This study highlighted the ongoing opportunity for health care organizations to conduct evidence-based practice inquiries to continually optimize care for their patients.

Even with recent pharmacologic treatment advances, narrowband UVB (NB-UVB) phototherapy remains a versatile, safe, and efficacious adjunctive or exclusive treatment for multiple dermatologic conditions, including psoriasis and atopic dermatitis. ^1-9 Some providers choose NB-UVB phototherapy as a first-line treatment for older adult patients who frequently use multiple treatment modalities for more than 1 health condition. Older adults with atopic dermatitis and psoriasis are at higher risk for comorbidities such as autoimmune disorders, diabetes mellitus, dyslipidemia, sleep disorders, neuropsychiatric disorders, and cardiovascular disease that can complicate treatment compared with their peers without these dermatologic diagnoses. ^10-12 Polypharmacy (ie, the use of 5 or more daily medications), frequently associated with these conditions, contributes to prescribers pursuing NB-UVB phototherapy as a nonpharmacologic treatment, but some providers wonder if it is as effective and safe for their older patients compared with younger patients.

In a prior study, Matthews et al¹³ reported that 96% (50/52) of patients older than 65 years achieved medium to high levels of clearance with NB-UVB phototherapy. Nonetheless, 2 other findings in this study related to the number of treatments required to achieve clearance (ie, clearance rates) and erythema rates prompted further investigation. The first finding was higher-than-expected clearance rates. Older adults had a clearance rate with a mean of 33 treatments compared to prior studies featuring mean clearance rates of 20 to 28 treatments.^7,8,14-16 This finding resembled a study in the United Kingdom¹⁷ with a median clearance rate in older adults of 30 treatments. In contrast, the median clearance rate from a study in Turkey¹⁸ was 42 treatments in older adults. We hypothesized that more photosensitizing medications used in older vs younger adults prompted more dose adjustments with NB-UVB phototherapy to avoid burning (ie, erythema) at baseline and throughout the treatment course. These dose adjustments may have increased the overall clearance rates. If true, we predicted that younger adults treated with the same protocol would have cleared more quickly, either because of age-related differences or because they likely had fewer comorbidities and therefore fewer medications.

The second finding from Matthews et al¹³ that warranted further investigation was a higher erythema rate compared to the older adult study from the United Kingdom.¹⁷ We hypothesized that potentially greater use of photosensitizing medications in the United States could explain the higher erythema rates. Although medication-induced photosensitivity is less likely with NB-UVB phototherapy than with UVA, certain medications can cause UVB photosensitivity, including thiazides, quinidine, calcium channel antagonists, phenothiazines, and nonsteroidal anti-inflammatory drugs.^8,19,20 Therefore, photosensitizing medication use either at baseline or during a course of NB-UVB phototherapy could increase the risk for erythema. Age-related skin changes also have been considered as a potential cause for erythema. One study found that the skin of older patients was more sensitive than younger patients, resulting in a lower minimal erythema dose (MED)¹⁴—the lowest UV dose that results in erythema.²¹ Others, however, found similar MEDs across age groups, but older adults experienced more intense erythema in the late phase of NB-UVB treatment.^22,23 Such conflicting findings indicate that questions remain regarding the risk for erythema in older patients and if photosensitizing medications are responsible for an increased risk.

This retrospective study aimed to determine if NB-UVB phototherapy is equally effective in both older and younger adults treated with the same protocol; to examine the association between the use of photosensitizing medications and clearance rates in both older and younger adults; and to examine the association between the use of photosensitizing medications and erythema rates in older vs younger adults.

Methods

Study Design and Patients—This retrospective cohort study used billing records to identify patients who received NB-UVB phototherapy at 3 different clinical sites within a large US health care system in Washington (Group Health Cooperative, now Kaiser Permanente Washington), serving more than 600,000 patients between January 1, 2012, and December 31, 2016. The institutional review board of Kaiser Permanente Washington Health Research Institute approved this study (IRB 1498087-4). Younger adults were classified as those 64 years or younger and older adults as those 65 years and older at the start of their phototherapy regimen. A power analysis determined that the optimal sample size for this study was 250 patients.

Individuals were excluded if they had fewer than 6 phototherapy treatments; a diagnosis of vitiligo, photosensitivity dermatitis, morphea, or pityriasis rubra pilaris; and/or treatment of the hands or feet only.

Phototherapy Protocol—Using a 48-lamp NB-UVB unit, trained phototherapy nurses provided all treatments following standardized treatment protocols¹³ based on previously published phototherapy guidelines.²⁴ Nurses determined each patient’s disease clearance level using a 3-point clearance scale (high, medium, low).¹³ Each patient’s starting dose was determined based on the estimated MED for their skin phototype. If the patient was using photosensitizing medications, the protocol indicated a need for a decreased starting dose—down 25% to 50%—depending on the presumed level of photosensitivity. All clinical sites used the same protocol, but decisions about adjustments within this range were made by individual registered nurses and dermatologists, which could lead to variability across sites. Protocols also directed nurses to query patients about specific treatment responses, including erythema, tenderness, or itching; how their condition was responding; use of photosensitizing medications; missed treatments; and placement of shielding. Doses were adjusted accordingly.

Statistical Analysis—Data were analyzed using Stata statistical software (StataCorp LLC). Univariate analyses were used to examine the data and identify outliers, bad values, and missing data, as well as to calculate descriptive statistics. Pearson χ² and Fisher exact statistics were used to calculate differences in categorical variables. Linear multivariate regression models and logistic multivariate models were used to examine statistical relationships between variables. Statistical significance was defined as P≤.05.

Results

Patient Characteristics—Medical records were reviewed for 172 patients who received phototherapy between 2012 and 2016. Patients ranged in age from 23 to 91 years, with 102 patients 64 years and younger and 70 patients 65 years and older. Tables 1 and 2 outline the patient characteristics and conditions treated.

Phototherapy Effectiveness—Narrowband UVB phototherapy was found to be equally effective in older vs younger adults, with 82.9% of older adults (n=58) achieving a high level of clearance vs 80.4% (n=82) of younger adults, and 5.7% (n=4) of older adults achieved a medium level of clearance vs 10% (n=10) of younger adults (Table 3). Although older adults had slightly faster clearance rates on average (34.6 vs 37.2 treatments), these differences were not significant.

Photosensitizing Medications, Clearance Levels, and Clearance Rates—There was no significant association between clearance levels and number of photosensitizing medications in either younger (Figure 1) or older (Figure 2) adults. There was a wide range of clearance rates in both groups (Table 3), but no relationship was identified between clearance rates and photosensitizing medications or age (Figure 3). Clinic C had higher overall clearance rates for both age groups compared to the other clinics (Figure 4), but the clearance levels were still equivalent. No consistent pattern emerged indicating that age was a factor for the slower clearance at this site, and no relationship was identified between taking photosensitizing medications and clearance levels (Fisher exact test, P=.467) or clearance rates (t[149]=0.75; P=.45).

Frequency of Treatments and Clearance Rates—Older adults more consistently completed the recommended frequency of treatments—3 times weekly—compared to younger adults (74.3% vs 58.5%). However, all patients who completed 3 treatments per week required a similar number of treatments to clear (older adults, mean [SD]: 35.7 [21.6]; younger adults, mean [SD]: 34.7 [19.0]; P=.85). Among patients completing 2 or fewer treatments per week, older adults required a mean (SD) of only 31 (9.0) treatments to clear vs 41.5 (21.3) treatments to clear for younger adults, but the difference was not statistically significant (P=.08). However, even those with suboptimal frequency ultimately achieved similar clearance levels.

Photosensitizing Medications and Erythema Rates—Many patients in both age groups took medications that listed photosensitivity as a potential side effect (77.1% of older adults and 60.8% of younger adults). Of them, most patients took only 1 or 2 photosensitizing medications. However, significantly more older patients took 3 or more photosensitizing medications (28.6% vs 12.7%; P=.01)(Table 3). Asymptomatic (grade 1) erythema was unrelated to medication use and quite common in all adults (48.6% of older adults and 60.8% of younger adults). Most patients had only a few episodes of grade 1 erythema (mean [SD], 1.2 [2.9] in older adults and 1.6 [2.2] in younger adults). More older adults had grade 2 erythema (28.6%) compared to younger adults (17.6%). Patients using 3 or more photosensitizing medications were twice as likely to experience grade 2 erythema. Grades 3 and 4 erythema were extremely rare; none of the patients stopped phototherapy because they experienced erythema.

Overall, phototherapy nurses adjusted the starting dose according to the phototype-based protocol an average of 69% of the time for patients on medications with photosensitivity listed as a potential side effect. However, the frequency depended significantly on the clinic (clinic A, 24%; clinic B, 92%; clinic C, 87%)(P≤.001). Nurses across all clinics consistently decreased the treatment dose when patients reported starting new photosensitizing medications. Patients with adjusted starting doses had slightly but not significantly higher clearance rates compared to those without (mean, 37.8 vs 35.5; t(104)=0.58; P=.56).

Comment

Comparisons to Prior Studies—This study confirmed that phototherapy is equally effective for older and younger adults, with approximately 90% reaching medium to high clearance levels with approximately 35 treatments in both groups. Prior studies of all age groups found that patients typically cleared with an average of 20 to 28 treatments.^7,8,14-16 In contrast, the findings in older adults from this study were similar to the older adult study from the United Kingdom that reported a 91% clear/near clear rate with an average of 30 treatments.¹⁷ The clearance level also was similar to the older adult study in Turkey¹⁸ that reported 73.7% (70/95) of patients with psoriasis achieved a minimum psoriasis area severity index of 75, indicating 75% improvement from baseline.

Impact of Photosensitizing Medications on Clearance—Photosensitizing medications and treatment frequency were 2 factors that might explain the slower clearance rates in younger adults. In this study, both groups of patients used similar numbers of photosensitizing medications, but more older adults were taking 3 or more medications (Table 3). We found no statistically significant relationship between taking photosensitizing medications and either the clearance rates or the level of clearance achieved in either age group.

Impact of Treatment Frequency—Weekly treatment frequency also was examined. One prior study demonstrated that treatments 3 times weekly led to a faster clearance time and higher clearance levels compared with twice-weekly treatment.⁷ When patients completed treatments twice weekly, it took an average of 1.5 times more days to clear, which impacted cost and clinical resource availability. The patients ranged in age from 17 to 80 years, but outcomes in older patients were not described separately.⁷ Interestingly, our study seemed to find a difference between age groups when the impact of treatment frequency was examined. Older adults completed nearly 4 fewer mean treatments to clear when treating less often, with more than 80% achieving high levels of clearance, whereas the younger adults required almost 7 more treatments to clear when they came in less frequently, with approximately 80% achieving a high level of clearance. As a result, our study found that in both age groups, slowing the treatment frequency extended the treatment time to clearance—more for the younger adults than the older adults—but did not significantly change the percentage of individuals reaching full clearance in either group.

Erythema Rates—There was no association between photosensitizing medications and erythema rates except when patients were taking at least 3 medications. Most medications that listed photosensitivity as a possible side effect did not specify their relevant range of UV radiation; therefore, all such medications were examined during this analysis. Prior research has shown UVB range photosensitizing medications include thiazides, quinidine, calcium channel antagonists, phenothiazines, and nonsteroidal anti-inflammatory drugs.¹⁹ A sensitivity analysis that focused only on these medications found no association between them and any particular grade of erythema. However, patients taking 3 or more of any medications listing photosensitivity as a side effect had an increased risk for grade 2 erythema.

Erythema rates in this study were consistent with a 2013 systematic review that reported 57% of patients with asymptomatic grade 1 erythema.²⁵ In the 2 other comparative older adult studies, erythema rates varied widely: 35% in a study from Turkey¹⁸compared to only1.89% in a study from the United Kingdom.¹⁷

The starting dose for NB-UVB may drive erythema rates. The current study’s protocols were based on an estimated MED that is subjectively determined by the dermatology provider’s assessment of the patient’s skin sensitivity via examination and questions to the patient about their response to environmental sun exposure (ie, burning and tanning)²⁶ and is frequently used to determine the starting dose and subsequent dose escalation. Certain medications have been found to increase photosensitivity and erythema,²⁰ which can change an individual’s MED. If photosensitizing medications are started prior to or during a course of NB-UVB without a pretreatment MED, they might increase the risk for erythema. This study did not identify specific erythema-inducing medications but did find that taking 3 or more photosensitizing medications was associated with increased episodes of grade 2 erythema. Similarly, Harrop et al⁸ found that patients who were taking photosensitizing medications were more likely to have grade 2 or higher erythema, despite baseline MED testing, which is an established safety mechanism to reduce the risk and severity of erythema.^14,20,27 The authors of a recent study of older adults in Taiwan specifically recommended MED testing due to the unpredictable influence of polypharmacy on MED calculations in this population.²⁸ Therefore, this study’s use of an estimated MED in older adults may have influenced the starting dose as well as the incidence and severity of erythemic events. Age-related skin changes likely are ruled out as a consideration for mild erythema by the similarity of grade 1 erythema rates in both older and younger adults. Other studies have identified differences between the age groups, where older patients experienced more intense erythema in the late phase of UVB treatments.^22,23 This phenomenon could increase the risk for a grade 2 erythema, which may correspond with this study’s findings.

Other potential causes of erythema were ruled out during our study, including erythema related to missed treatments and shielding mishaps. Other factors, however, may impact the level of sensitivity each patient has to phototherapy, including genetics, epigenetics, and cumulative sun damage. With NB-UVB, near-erythemogenic doses are optimal to achieve effective treatments but require a delicate balance to achieve, which may be more problematic for older adults, especially those taking several medications.

Study Limitations—Our study design made it difficult to draw conclusions about rarer dermatologic conditions. Some patients received treatments over years that were not included in the study period. Finally, power calculations suggested that our actual sample size was too small, with approximately one-third of the required sample missing.

Practical Implications—The goals of phototherapy are to achieve a high level of disease clearance with the fewest number of treatments possible and minimal side effects. Skin phototype–driven standardized doses based on estimated MED may be conservatively low to minimize the risk of side effects (eg, erythema), which could slow the treatment progression. Thus, basing the starting dose on individual MED assessments may improve clearance rates. This study also confirmed that phototherapy is safe with minimal erythema in adults of all ages. The erythema episodes that patients experienced were few and mild, but because of greater rates of grade 2 erythema in patients on 3 or more photosensitizing medications, consideration of MED testing in both age groups might optimize doses at baseline and prompt caution for subsequent dose titration in this subset of patients.

The extra staff training and patient monitoring required for MED testing likely is to add value and preserve resources if faster clearance rates could be achieved and may warrant further investigation. Phototherapy centers require standardized treatment protocols, diligent well-trained staff, and program monitoring to ensure consistent care to all patients. This study highlighted the ongoing opportunity for health care organizations to conduct evidence-based practice inquiries to continually optimize care for their patients.

Even with recent pharmacologic treatment advances, narrowband UVB (NB-UVB) phototherapy remains a versatile, safe, and efficacious adjunctive or exclusive treatment for multiple dermatologic conditions, including psoriasis and atopic dermatitis. ^1-9 Some providers choose NB-UVB phototherapy as a first-line treatment for older adult patients who frequently use multiple treatment modalities for more than 1 health condition. Older adults with atopic dermatitis and psoriasis are at higher risk for comorbidities such as autoimmune disorders, diabetes mellitus, dyslipidemia, sleep disorders, neuropsychiatric disorders, and cardiovascular disease that can complicate treatment compared with their peers without these dermatologic diagnoses. ^10-12 Polypharmacy (ie, the use of 5 or more daily medications), frequently associated with these conditions, contributes to prescribers pursuing NB-UVB phototherapy as a nonpharmacologic treatment, but some providers wonder if it is as effective and safe for their older patients compared with younger patients.

In a prior study, Matthews et al¹³ reported that 96% (50/52) of patients older than 65 years achieved medium to high levels of clearance with NB-UVB phototherapy. Nonetheless, 2 other findings in this study related to the number of treatments required to achieve clearance (ie, clearance rates) and erythema rates prompted further investigation. The first finding was higher-than-expected clearance rates. Older adults had a clearance rate with a mean of 33 treatments compared to prior studies featuring mean clearance rates of 20 to 28 treatments.^7,8,14-16 This finding resembled a study in the United Kingdom¹⁷ with a median clearance rate in older adults of 30 treatments. In contrast, the median clearance rate from a study in Turkey¹⁸ was 42 treatments in older adults. We hypothesized that more photosensitizing medications used in older vs younger adults prompted more dose adjustments with NB-UVB phototherapy to avoid burning (ie, erythema) at baseline and throughout the treatment course. These dose adjustments may have increased the overall clearance rates. If true, we predicted that younger adults treated with the same protocol would have cleared more quickly, either because of age-related differences or because they likely had fewer comorbidities and therefore fewer medications.

The second finding from Matthews et al¹³ that warranted further investigation was a higher erythema rate compared to the older adult study from the United Kingdom.¹⁷ We hypothesized that potentially greater use of photosensitizing medications in the United States could explain the higher erythema rates. Although medication-induced photosensitivity is less likely with NB-UVB phototherapy than with UVA, certain medications can cause UVB photosensitivity, including thiazides, quinidine, calcium channel antagonists, phenothiazines, and nonsteroidal anti-inflammatory drugs.^8,19,20 Therefore, photosensitizing medication use either at baseline or during a course of NB-UVB phototherapy could increase the risk for erythema. Age-related skin changes also have been considered as a potential cause for erythema. One study found that the skin of older patients was more sensitive than younger patients, resulting in a lower minimal erythema dose (MED)¹⁴—the lowest UV dose that results in erythema.²¹ Others, however, found similar MEDs across age groups, but older adults experienced more intense erythema in the late phase of NB-UVB treatment.^22,23 Such conflicting findings indicate that questions remain regarding the risk for erythema in older patients and if photosensitizing medications are responsible for an increased risk.

This retrospective study aimed to determine if NB-UVB phototherapy is equally effective in both older and younger adults treated with the same protocol; to examine the association between the use of photosensitizing medications and clearance rates in both older and younger adults; and to examine the association between the use of photosensitizing medications and erythema rates in older vs younger adults.

Methods

Study Design and Patients—This retrospective cohort study used billing records to identify patients who received NB-UVB phototherapy at 3 different clinical sites within a large US health care system in Washington (Group Health Cooperative, now Kaiser Permanente Washington), serving more than 600,000 patients between January 1, 2012, and December 31, 2016. The institutional review board of Kaiser Permanente Washington Health Research Institute approved this study (IRB 1498087-4). Younger adults were classified as those 64 years or younger and older adults as those 65 years and older at the start of their phototherapy regimen. A power analysis determined that the optimal sample size for this study was 250 patients.

Individuals were excluded if they had fewer than 6 phototherapy treatments; a diagnosis of vitiligo, photosensitivity dermatitis, morphea, or pityriasis rubra pilaris; and/or treatment of the hands or feet only.

Phototherapy Protocol—Using a 48-lamp NB-UVB unit, trained phototherapy nurses provided all treatments following standardized treatment protocols¹³ based on previously published phototherapy guidelines.²⁴ Nurses determined each patient’s disease clearance level using a 3-point clearance scale (high, medium, low).¹³ Each patient’s starting dose was determined based on the estimated MED for their skin phototype. If the patient was using photosensitizing medications, the protocol indicated a need for a decreased starting dose—down 25% to 50%—depending on the presumed level of photosensitivity. All clinical sites used the same protocol, but decisions about adjustments within this range were made by individual registered nurses and dermatologists, which could lead to variability across sites. Protocols also directed nurses to query patients about specific treatment responses, including erythema, tenderness, or itching; how their condition was responding; use of photosensitizing medications; missed treatments; and placement of shielding. Doses were adjusted accordingly.

Statistical Analysis—Data were analyzed using Stata statistical software (StataCorp LLC). Univariate analyses were used to examine the data and identify outliers, bad values, and missing data, as well as to calculate descriptive statistics. Pearson χ² and Fisher exact statistics were used to calculate differences in categorical variables. Linear multivariate regression models and logistic multivariate models were used to examine statistical relationships between variables. Statistical significance was defined as P≤.05.

Results

Patient Characteristics—Medical records were reviewed for 172 patients who received phototherapy between 2012 and 2016. Patients ranged in age from 23 to 91 years, with 102 patients 64 years and younger and 70 patients 65 years and older. Tables 1 and 2 outline the patient characteristics and conditions treated.

Phototherapy Effectiveness—Narrowband UVB phototherapy was found to be equally effective in older vs younger adults, with 82.9% of older adults (n=58) achieving a high level of clearance vs 80.4% (n=82) of younger adults, and 5.7% (n=4) of older adults achieved a medium level of clearance vs 10% (n=10) of younger adults (Table 3). Although older adults had slightly faster clearance rates on average (34.6 vs 37.2 treatments), these differences were not significant.

Photosensitizing Medications, Clearance Levels, and Clearance Rates—There was no significant association between clearance levels and number of photosensitizing medications in either younger (Figure 1) or older (Figure 2) adults. There was a wide range of clearance rates in both groups (Table 3), but no relationship was identified between clearance rates and photosensitizing medications or age (Figure 3). Clinic C had higher overall clearance rates for both age groups compared to the other clinics (Figure 4), but the clearance levels were still equivalent. No consistent pattern emerged indicating that age was a factor for the slower clearance at this site, and no relationship was identified between taking photosensitizing medications and clearance levels (Fisher exact test, P=.467) or clearance rates (t[149]=0.75; P=.45).

Frequency of Treatments and Clearance Rates—Older adults more consistently completed the recommended frequency of treatments—3 times weekly—compared to younger adults (74.3% vs 58.5%). However, all patients who completed 3 treatments per week required a similar number of treatments to clear (older adults, mean [SD]: 35.7 [21.6]; younger adults, mean [SD]: 34.7 [19.0]; P=.85). Among patients completing 2 or fewer treatments per week, older adults required a mean (SD) of only 31 (9.0) treatments to clear vs 41.5 (21.3) treatments to clear for younger adults, but the difference was not statistically significant (P=.08). However, even those with suboptimal frequency ultimately achieved similar clearance levels.

Photosensitizing Medications and Erythema Rates—Many patients in both age groups took medications that listed photosensitivity as a potential side effect (77.1% of older adults and 60.8% of younger adults). Of them, most patients took only 1 or 2 photosensitizing medications. However, significantly more older patients took 3 or more photosensitizing medications (28.6% vs 12.7%; P=.01)(Table 3). Asymptomatic (grade 1) erythema was unrelated to medication use and quite common in all adults (48.6% of older adults and 60.8% of younger adults). Most patients had only a few episodes of grade 1 erythema (mean [SD], 1.2 [2.9] in older adults and 1.6 [2.2] in younger adults). More older adults had grade 2 erythema (28.6%) compared to younger adults (17.6%). Patients using 3 or more photosensitizing medications were twice as likely to experience grade 2 erythema. Grades 3 and 4 erythema were extremely rare; none of the patients stopped phototherapy because they experienced erythema.

Overall, phototherapy nurses adjusted the starting dose according to the phototype-based protocol an average of 69% of the time for patients on medications with photosensitivity listed as a potential side effect. However, the frequency depended significantly on the clinic (clinic A, 24%; clinic B, 92%; clinic C, 87%)(P≤.001). Nurses across all clinics consistently decreased the treatment dose when patients reported starting new photosensitizing medications. Patients with adjusted starting doses had slightly but not significantly higher clearance rates compared to those without (mean, 37.8 vs 35.5; t(104)=0.58; P=.56).

Comment

Comparisons to Prior Studies—This study confirmed that phototherapy is equally effective for older and younger adults, with approximately 90% reaching medium to high clearance levels with approximately 35 treatments in both groups. Prior studies of all age groups found that patients typically cleared with an average of 20 to 28 treatments.^7,8,14-16 In contrast, the findings in older adults from this study were similar to the older adult study from the United Kingdom that reported a 91% clear/near clear rate with an average of 30 treatments.¹⁷ The clearance level also was similar to the older adult study in Turkey¹⁸ that reported 73.7% (70/95) of patients with psoriasis achieved a minimum psoriasis area severity index of 75, indicating 75% improvement from baseline.

Impact of Photosensitizing Medications on Clearance—Photosensitizing medications and treatment frequency were 2 factors that might explain the slower clearance rates in younger adults. In this study, both groups of patients used similar numbers of photosensitizing medications, but more older adults were taking 3 or more medications (Table 3). We found no statistically significant relationship between taking photosensitizing medications and either the clearance rates or the level of clearance achieved in either age group.

Impact of Treatment Frequency—Weekly treatment frequency also was examined. One prior study demonstrated that treatments 3 times weekly led to a faster clearance time and higher clearance levels compared with twice-weekly treatment.⁷ When patients completed treatments twice weekly, it took an average of 1.5 times more days to clear, which impacted cost and clinical resource availability. The patients ranged in age from 17 to 80 years, but outcomes in older patients were not described separately.⁷ Interestingly, our study seemed to find a difference between age groups when the impact of treatment frequency was examined. Older adults completed nearly 4 fewer mean treatments to clear when treating less often, with more than 80% achieving high levels of clearance, whereas the younger adults required almost 7 more treatments to clear when they came in less frequently, with approximately 80% achieving a high level of clearance. As a result, our study found that in both age groups, slowing the treatment frequency extended the treatment time to clearance—more for the younger adults than the older adults—but did not significantly change the percentage of individuals reaching full clearance in either group.

Erythema Rates—There was no association between photosensitizing medications and erythema rates except when patients were taking at least 3 medications. Most medications that listed photosensitivity as a possible side effect did not specify their relevant range of UV radiation; therefore, all such medications were examined during this analysis. Prior research has shown UVB range photosensitizing medications include thiazides, quinidine, calcium channel antagonists, phenothiazines, and nonsteroidal anti-inflammatory drugs.¹⁹ A sensitivity analysis that focused only on these medications found no association between them and any particular grade of erythema. However, patients taking 3 or more of any medications listing photosensitivity as a side effect had an increased risk for grade 2 erythema.

Erythema rates in this study were consistent with a 2013 systematic review that reported 57% of patients with asymptomatic grade 1 erythema.²⁵ In the 2 other comparative older adult studies, erythema rates varied widely: 35% in a study from Turkey¹⁸compared to only1.89% in a study from the United Kingdom.¹⁷

The starting dose for NB-UVB may drive erythema rates. The current study’s protocols were based on an estimated MED that is subjectively determined by the dermatology provider’s assessment of the patient’s skin sensitivity via examination and questions to the patient about their response to environmental sun exposure (ie, burning and tanning)²⁶ and is frequently used to determine the starting dose and subsequent dose escalation. Certain medications have been found to increase photosensitivity and erythema,²⁰ which can change an individual’s MED. If photosensitizing medications are started prior to or during a course of NB-UVB without a pretreatment MED, they might increase the risk for erythema. This study did not identify specific erythema-inducing medications but did find that taking 3 or more photosensitizing medications was associated with increased episodes of grade 2 erythema. Similarly, Harrop et al⁸ found that patients who were taking photosensitizing medications were more likely to have grade 2 or higher erythema, despite baseline MED testing, which is an established safety mechanism to reduce the risk and severity of erythema.^14,20,27 The authors of a recent study of older adults in Taiwan specifically recommended MED testing due to the unpredictable influence of polypharmacy on MED calculations in this population.²⁸ Therefore, this study’s use of an estimated MED in older adults may have influenced the starting dose as well as the incidence and severity of erythemic events. Age-related skin changes likely are ruled out as a consideration for mild erythema by the similarity of grade 1 erythema rates in both older and younger adults. Other studies have identified differences between the age groups, where older patients experienced more intense erythema in the late phase of UVB treatments.^22,23 This phenomenon could increase the risk for a grade 2 erythema, which may correspond with this study’s findings.

Other potential causes of erythema were ruled out during our study, including erythema related to missed treatments and shielding mishaps. Other factors, however, may impact the level of sensitivity each patient has to phototherapy, including genetics, epigenetics, and cumulative sun damage. With NB-UVB, near-erythemogenic doses are optimal to achieve effective treatments but require a delicate balance to achieve, which may be more problematic for older adults, especially those taking several medications.

Study Limitations—Our study design made it difficult to draw conclusions about rarer dermatologic conditions. Some patients received treatments over years that were not included in the study period. Finally, power calculations suggested that our actual sample size was too small, with approximately one-third of the required sample missing.

Practical Implications—The goals of phototherapy are to achieve a high level of disease clearance with the fewest number of treatments possible and minimal side effects. Skin phototype–driven standardized doses based on estimated MED may be conservatively low to minimize the risk of side effects (eg, erythema), which could slow the treatment progression. Thus, basing the starting dose on individual MED assessments may improve clearance rates. This study also confirmed that phototherapy is safe with minimal erythema in adults of all ages. The erythema episodes that patients experienced were few and mild, but because of greater rates of grade 2 erythema in patients on 3 or more photosensitizing medications, consideration of MED testing in both age groups might optimize doses at baseline and prompt caution for subsequent dose titration in this subset of patients.

The extra staff training and patient monitoring required for MED testing likely is to add value and preserve resources if faster clearance rates could be achieved and may warrant further investigation. Phototherapy centers require standardized treatment protocols, diligent well-trained staff, and program monitoring to ensure consistent care to all patients. This study highlighted the ongoing opportunity for health care organizations to conduct evidence-based practice inquiries to continually optimize care for their patients.

Identifying safe, effective, and affordable evidence-based dermatologic treatments for older adults can be challenging because of age-related changes in the skin, comorbidities, polypharmacy, mobility issues, and cognitive changes. Phototherapy has been shown to be an effective nonpharmacologic treatment option for multiple challenging dermatologic conditions^1-8; however, few studies have specifically examined its effectiveness in older adults. The challenge for older patients with psoriasis and dermatitis is that the conditions can be difficult to control and often require multiple treatment modalities.^9,10 Patients with psoriasis also have a higher risk for diabetes, dyslipidemia, and cardiovascular disease compared to other older patients,^11,12 which poses treatment challenges and makes nonpharmacologic treatments even more appealing.

Recent studies show that phototherapy can help decrease the use of dermatologic medications. Foerster and colleagues² found that adults with psoriasis who were treated with phototherapy significantly decreased their use of topical steroids (24.5% fewer patients required steroid creams and 31.1% fewer patients required psoriasis-specific topicals)(P<.01) while their use of non–psoriasis-specific medications did not change. Click and colleagues¹³ identified a decrease in medication costs, health care utilization, and risk for immunosuppression in patients treated with phototherapy when compared to those treated with biologics and apremilast. Methotrexate is a common dermatologic medication that is highly associated with increased risks in elderly patients because of impaired immune system function and the presence of comorbidities (eg, kidney disease, obesity, diabetes, fatty liver),¹⁴ which increase in prevalence with age. Combining phototherapy with methotrexate can substantially decrease the amount of methotrexate needed to achieve disease control,¹⁵ thereby decreasing the methotrexate-associated risks. Findings from these studies suggest that a safe, effective, cost-effective, and well-tolerated nonpharmacologic alternative, such as phototherapy, is highly desirable and should be optimized. Unfortunately, most studies that report the effectiveness of phototherapy are in younger populations.

This retrospective study aimed to (1) identify the most common dermatologic conditions treated with phototherapy in older adults, (2) examine the effectiveness and safety of phototherapy in older adults, and (3) compare the outcomes with 2 similar studies in the United Kingdom¹⁶ and Turkey.¹⁷

Methods

Design, Setting, Sample, and Statistical Analysis
The institutional review boards of Kaiser Permanente Washington Health Research Institute, Seattle, and the University of Washington, Seattle, approved this study. It was conducted in a large US multispecialty health care system (Group Health, Seattle, Washington [now Kaiser Permanente Washington]) serving approximately 600,000 patients, using billing records to identify all patients treated with phototherapy between January 1, 2015, and December 31, 2015, all who received narrowband UVB (NB-UVB) phototherapy. All adults 65 years and older who received phototherapy treatment during the 12-month study period were included. Patients were included regardless of comorbidities and other dermatologic treatments to maintain as much uniformity as possible between the present study and 2 prior studies examining phototherapy in older adult populations in the United Kingdom¹⁶ and Turkey.¹⁷ Demographic and clinical factors were presented using frequencies (percentages) or means and medians as appropriate. Comparisons of dermatologic conditions and clearance levels used a Fisher exact test. The number of phototherapy treatments to clearance and total number of treatments were compared between groups of patients using independent sample t tests.

Phototherapy Protocol
All patients received treatments administered by specially trained phototherapy nurses using a Daavlin UV Series (The Daavlin Company) or an Ultralite unit (Ultralite Enterprises, Inc), both with 48 lamps. All phototherapy nurses had been previously trained to provide treatments based on standardized protocols (Table 1) and to determine the patient’s level of disease clearance using a high to low clearance scale (Table 2). Daavlin’s treatment protocols were built into the software that accompanied the units and were developed based on the American Academy of Dermatology guidelines. The starting dose for an individual patient was determined based on the estimated minimal erythema dose for each phototype. If the patient was using photosensitizing medications, then the protocol guided the nurse to start the patient at a lower dose appropriate for their phototype. Patients with vitiligo were treated with the same starting and escalation doses as patients with Fitzpatrick phototype I because of the assumption that their vitiliginous skin had an increased risk for photosensitivity. A more recent review of the evidence has indicated that this assumption was overly conservative,¹⁸ and Kaiser Permanente Washington’s vitiligo protocol has been adjusted.

Results

Patients
Billing records identified 229 total patients who received phototherapy in 2015, of whom 52 (22.7%) were at least 65 years old. The median age was 70 years (range, 65–91 years). Twenty-nine (56%) were men and 35 (67%) had previously received phototherapy treatments.

Dermatologic Conditions Treated With Phototherapy
Our primary aim was to identify the most common dermatologic conditions treated with phototherapy in older adults. Psoriasis and dermatitis were the most common conditions treated in the sample (50% [26/52] and 21% [11/52], respectively), with mycosis fungoides being the third most common (10% [5/52]) and vitiligo tied with prurigo nodularis as fourth most common (6% [3/52])(Figure 1).

Effectiveness and Safety of Phototherapy
Our secondary aim was to examine the effectiveness and safety of phototherapy in older adults. Phototherapy was effective in this population, with 50 of 52 patients (96%) achieving a high or medium level of clearance. The degree of clearance for each of the dermatologic conditions is shown in Figure 2. Psoriasis and dermatitis achieved high clearance rates in 81% (21/26) and 82% (9/11) of patients, respectively. Overall, conditions did not have significant differences in clearances rates (Fisher exact test, P=.10). On average, it took patients 33 treatments to achieve medium or high rates of clearance. Psoriasis cleared more quickly, with an average of 30.4 treatments vs 36.1 treatments for other conditions, but the difference was not significant (t test, P=.26). Patients received an average of 98 total phototherapy treatments; the median number of treatments was 81 due to many being on maintenance therapy over several months. There was no relationship between a history of treatment with phototherapy and the total number of treatments needed to achieve clearance (t test, P=.40), but interestingly, those who had a history of phototherapy took approximately 5 more treatments to achieve clearance. The present study found that a slightly larger number of men were being treated for psoriasis (15 men vs 11 women), but there was no significant difference in response rate based on gender.

Comment

Our study found that 94% of patients with psoriasis achieved clearance with an average of 30.4 treatments, which is comparable to the reported 91% response rate with an average of 30 treatments in the United Kingdom.¹⁶ The other similar study in Turkey¹⁷ reported 73.7% of psoriasis patients achieved a 75% or more improvement from baseline with an average of 42 treatments, which may reflect underlying differences in regional skin type. Of note, the scatter chart (Figure 3) shows that several patients in the present study’s analysis are listed as not clear, but many of those patients had low treatment numbers below the mean time to clearance. Thus, the present study’s response rate may have been underestimated.

In the general population, studies show that psoriasis treated with standardized phototherapy protocols typically clears with an average of 20.6 treatments.²¹ The levels of clearance were similar in our study’s older population, but more treatments were required to achieve those results, with an average of 10 more treatments needed (an additional 3.3 weeks). Similar results were found in this sample for dermatitis and mycosis fungoides, indicating comparable clearance rates and levels but a need for more treatments to achieve similar results compared to the general population.

Additionally, in the current study more patients experienced grade 1 (mild) erythema (46%) and grade 2 erythema (25%) at some point in their treatment compared with the United Kingdom¹⁶ (1.89%) and Turkey¹⁷ (35%) studies, though these side effects did not impact the clearance rate. Interestingly, the current study’s scatter chart (Figure 3) illustrates that this side effect did not seem to increase with aging in this population. If anything, the erythema response was more prevalent in the median or younger patients in the sample. Erythema may have been due to the frequent use of photosensitizing medications in older adults in the United States, some of which typically get discontinued in patients 75 years and older (eg, statins). Other potential causes might include the use of phototype vs minimal erythema dose–driven protocols, the standard utilization of protocols originally designed for psoriasis vs other condition-specific protocols, missed treatments leading to increased sensitivity, or possibly shielding mishaps (eg, not wearing a prescribed face shield). Given the number of potential causes and the possibility of overlapping factors, careful analysis is important. With NB-UVB phototherapy, near-erythemogenic doses are optimal to achieve effective treatments, but this delicate balance may be more problematic for older adults. Future studies are needed to fully determine the factors at play for this population. In the interim, it is important for phototherapy-trained nurses to consider this risk carefully in the older population. They must follow the prescribed protocols that guide them to query patients about their responses to the prior treatment (eg, erythema, tenderness, itching), photosensitizing medications, missed treatments, and placement of shielding, and then adjust the treatment dosing accordingly.

Limitations
This study had several limitations. Although clinical outcomes were recorded prospectively, the analysis was retrospective, unblinded, and not placebo controlled. It was conducted in a single organization (Group Health [now Kaiser Permanente Washington]) but did analyze data from 4 medical centers in different cities with diverse demographics and a variety of nursing staff providing the treatments. Although the vitiligo treatment protocol likely slowed the response rate for those patients with vitiligo, the numbers were small (ie, only 3 of 52 patients), so the researchers chose to include them in the current study. The sample population was relatively small, but when these data are evaluated alongside the studies in the United Kingdom¹⁶ and Turkey,¹⁷ they show a consistent picture illustrating the effectiveness and safety of phototherapy in the older population. Further epidemiologic studies could be helpful to further describe the usefulness of this modality compared with other treatments for a variety of dermatoses in this age group. Supplementary analysis specifically examining the relationship between the number and type of photosensitizing medications, frequency of erythema, and time to clearance also could be useful.

Conclusion

Older adults with a variety of dermatoses respond well to phototherapy and should have the opportunity to use it, particularly considering the potential for increased complications and costs from other treatment modalities, such as commonly used immunosuppressive pharmaceuticals. However, the current study and the comparison studies indicate that it is important to carefully consider the slower clearance rates and the potential risk for increased erythema in this population and adjust patient education and treatment dosing accordingly.

Unfortunately, many dermatology centers do not offer phototherapy because of infrastructure limitations such as space and specially trained nursing staff. Increasing accessibility of phototherapy for older adults through home treatments may be an alternative, given its effectiveness in the general population.^22,23 In addition, home phototherapy may be worth pursuing for the older population considering the challenges they may face with transportation to the clinic setting and their increased risk for serious illness if exposed to infections such as COVID-19. The COVID-19 pandemic has brought to light the need for reliable, safe, and effective treatments that can be utilized in the safety of patients’ homes and should therefore be considered as an option for older adults. Issues such as mobility and cognitive decline could pose some complicating factors, but with the help of a well-trained family member or caregiver, home phototherapy could be a viable option that improves accessibility for older patients. Future research opportunities include further examination of the slower but ultimately equivalent response to phototherapy in the older population, the influence of photosensitizing medications on phototherapy effects, and the impact of phototherapy on utilization of immunosuppressive pharmaceuticals in older adults.

Identifying safe, effective, and affordable evidence-based dermatologic treatments for older adults can be challenging because of age-related changes in the skin, comorbidities, polypharmacy, mobility issues, and cognitive changes. Phototherapy has been shown to be an effective nonpharmacologic treatment option for multiple challenging dermatologic conditions^1-8; however, few studies have specifically examined its effectiveness in older adults. The challenge for older patients with psoriasis and dermatitis is that the conditions can be difficult to control and often require multiple treatment modalities.^9,10 Patients with psoriasis also have a higher risk for diabetes, dyslipidemia, and cardiovascular disease compared to other older patients,^11,12 which poses treatment challenges and makes nonpharmacologic treatments even more appealing.

Recent studies show that phototherapy can help decrease the use of dermatologic medications. Foerster and colleagues² found that adults with psoriasis who were treated with phototherapy significantly decreased their use of topical steroids (24.5% fewer patients required steroid creams and 31.1% fewer patients required psoriasis-specific topicals)(P<.01) while their use of non–psoriasis-specific medications did not change. Click and colleagues¹³ identified a decrease in medication costs, health care utilization, and risk for immunosuppression in patients treated with phototherapy when compared to those treated with biologics and apremilast. Methotrexate is a common dermatologic medication that is highly associated with increased risks in elderly patients because of impaired immune system function and the presence of comorbidities (eg, kidney disease, obesity, diabetes, fatty liver),¹⁴ which increase in prevalence with age. Combining phototherapy with methotrexate can substantially decrease the amount of methotrexate needed to achieve disease control,¹⁵ thereby decreasing the methotrexate-associated risks. Findings from these studies suggest that a safe, effective, cost-effective, and well-tolerated nonpharmacologic alternative, such as phototherapy, is highly desirable and should be optimized. Unfortunately, most studies that report the effectiveness of phototherapy are in younger populations.

This retrospective study aimed to (1) identify the most common dermatologic conditions treated with phototherapy in older adults, (2) examine the effectiveness and safety of phototherapy in older adults, and (3) compare the outcomes with 2 similar studies in the United Kingdom¹⁶ and Turkey.¹⁷

Methods

Design, Setting, Sample, and Statistical Analysis
The institutional review boards of Kaiser Permanente Washington Health Research Institute, Seattle, and the University of Washington, Seattle, approved this study. It was conducted in a large US multispecialty health care system (Group Health, Seattle, Washington [now Kaiser Permanente Washington]) serving approximately 600,000 patients, using billing records to identify all patients treated with phototherapy between January 1, 2015, and December 31, 2015, all who received narrowband UVB (NB-UVB) phototherapy. All adults 65 years and older who received phototherapy treatment during the 12-month study period were included. Patients were included regardless of comorbidities and other dermatologic treatments to maintain as much uniformity as possible between the present study and 2 prior studies examining phototherapy in older adult populations in the United Kingdom¹⁶ and Turkey.¹⁷ Demographic and clinical factors were presented using frequencies (percentages) or means and medians as appropriate. Comparisons of dermatologic conditions and clearance levels used a Fisher exact test. The number of phototherapy treatments to clearance and total number of treatments were compared between groups of patients using independent sample t tests.

Phototherapy Protocol
All patients received treatments administered by specially trained phototherapy nurses using a Daavlin UV Series (The Daavlin Company) or an Ultralite unit (Ultralite Enterprises, Inc), both with 48 lamps. All phototherapy nurses had been previously trained to provide treatments based on standardized protocols (Table 1) and to determine the patient’s level of disease clearance using a high to low clearance scale (Table 2). Daavlin’s treatment protocols were built into the software that accompanied the units and were developed based on the American Academy of Dermatology guidelines. The starting dose for an individual patient was determined based on the estimated minimal erythema dose for each phototype. If the patient was using photosensitizing medications, then the protocol guided the nurse to start the patient at a lower dose appropriate for their phototype. Patients with vitiligo were treated with the same starting and escalation doses as patients with Fitzpatrick phototype I because of the assumption that their vitiliginous skin had an increased risk for photosensitivity. A more recent review of the evidence has indicated that this assumption was overly conservative,¹⁸ and Kaiser Permanente Washington’s vitiligo protocol has been adjusted.

Results

Patients
Billing records identified 229 total patients who received phototherapy in 2015, of whom 52 (22.7%) were at least 65 years old. The median age was 70 years (range, 65–91 years). Twenty-nine (56%) were men and 35 (67%) had previously received phototherapy treatments.

Dermatologic Conditions Treated With Phototherapy
Our primary aim was to identify the most common dermatologic conditions treated with phototherapy in older adults. Psoriasis and dermatitis were the most common conditions treated in the sample (50% [26/52] and 21% [11/52], respectively), with mycosis fungoides being the third most common (10% [5/52]) and vitiligo tied with prurigo nodularis as fourth most common (6% [3/52])(Figure 1).

Effectiveness and Safety of Phototherapy
Our secondary aim was to examine the effectiveness and safety of phototherapy in older adults. Phototherapy was effective in this population, with 50 of 52 patients (96%) achieving a high or medium level of clearance. The degree of clearance for each of the dermatologic conditions is shown in Figure 2. Psoriasis and dermatitis achieved high clearance rates in 81% (21/26) and 82% (9/11) of patients, respectively. Overall, conditions did not have significant differences in clearances rates (Fisher exact test, P=.10). On average, it took patients 33 treatments to achieve medium or high rates of clearance. Psoriasis cleared more quickly, with an average of 30.4 treatments vs 36.1 treatments for other conditions, but the difference was not significant (t test, P=.26). Patients received an average of 98 total phototherapy treatments; the median number of treatments was 81 due to many being on maintenance therapy over several months. There was no relationship between a history of treatment with phototherapy and the total number of treatments needed to achieve clearance (t test, P=.40), but interestingly, those who had a history of phototherapy took approximately 5 more treatments to achieve clearance. The present study found that a slightly larger number of men were being treated for psoriasis (15 men vs 11 women), but there was no significant difference in response rate based on gender.

Comment

Our study found that 94% of patients with psoriasis achieved clearance with an average of 30.4 treatments, which is comparable to the reported 91% response rate with an average of 30 treatments in the United Kingdom.¹⁶ The other similar study in Turkey¹⁷ reported 73.7% of psoriasis patients achieved a 75% or more improvement from baseline with an average of 42 treatments, which may reflect underlying differences in regional skin type. Of note, the scatter chart (Figure 3) shows that several patients in the present study’s analysis are listed as not clear, but many of those patients had low treatment numbers below the mean time to clearance. Thus, the present study’s response rate may have been underestimated.

In the general population, studies show that psoriasis treated with standardized phototherapy protocols typically clears with an average of 20.6 treatments.²¹ The levels of clearance were similar in our study’s older population, but more treatments were required to achieve those results, with an average of 10 more treatments needed (an additional 3.3 weeks). Similar results were found in this sample for dermatitis and mycosis fungoides, indicating comparable clearance rates and levels but a need for more treatments to achieve similar results compared to the general population.

Additionally, in the current study more patients experienced grade 1 (mild) erythema (46%) and grade 2 erythema (25%) at some point in their treatment compared with the United Kingdom¹⁶ (1.89%) and Turkey¹⁷ (35%) studies, though these side effects did not impact the clearance rate. Interestingly, the current study’s scatter chart (Figure 3) illustrates that this side effect did not seem to increase with aging in this population. If anything, the erythema response was more prevalent in the median or younger patients in the sample. Erythema may have been due to the frequent use of photosensitizing medications in older adults in the United States, some of which typically get discontinued in patients 75 years and older (eg, statins). Other potential causes might include the use of phototype vs minimal erythema dose–driven protocols, the standard utilization of protocols originally designed for psoriasis vs other condition-specific protocols, missed treatments leading to increased sensitivity, or possibly shielding mishaps (eg, not wearing a prescribed face shield). Given the number of potential causes and the possibility of overlapping factors, careful analysis is important. With NB-UVB phototherapy, near-erythemogenic doses are optimal to achieve effective treatments, but this delicate balance may be more problematic for older adults. Future studies are needed to fully determine the factors at play for this population. In the interim, it is important for phototherapy-trained nurses to consider this risk carefully in the older population. They must follow the prescribed protocols that guide them to query patients about their responses to the prior treatment (eg, erythema, tenderness, itching), photosensitizing medications, missed treatments, and placement of shielding, and then adjust the treatment dosing accordingly.

Limitations
This study had several limitations. Although clinical outcomes were recorded prospectively, the analysis was retrospective, unblinded, and not placebo controlled. It was conducted in a single organization (Group Health [now Kaiser Permanente Washington]) but did analyze data from 4 medical centers in different cities with diverse demographics and a variety of nursing staff providing the treatments. Although the vitiligo treatment protocol likely slowed the response rate for those patients with vitiligo, the numbers were small (ie, only 3 of 52 patients), so the researchers chose to include them in the current study. The sample population was relatively small, but when these data are evaluated alongside the studies in the United Kingdom¹⁶ and Turkey,¹⁷ they show a consistent picture illustrating the effectiveness and safety of phototherapy in the older population. Further epidemiologic studies could be helpful to further describe the usefulness of this modality compared with other treatments for a variety of dermatoses in this age group. Supplementary analysis specifically examining the relationship between the number and type of photosensitizing medications, frequency of erythema, and time to clearance also could be useful.

Conclusion

Older adults with a variety of dermatoses respond well to phototherapy and should have the opportunity to use it, particularly considering the potential for increased complications and costs from other treatment modalities, such as commonly used immunosuppressive pharmaceuticals. However, the current study and the comparison studies indicate that it is important to carefully consider the slower clearance rates and the potential risk for increased erythema in this population and adjust patient education and treatment dosing accordingly.

Unfortunately, many dermatology centers do not offer phototherapy because of infrastructure limitations such as space and specially trained nursing staff. Increasing accessibility of phototherapy for older adults through home treatments may be an alternative, given its effectiveness in the general population.^22,23 In addition, home phototherapy may be worth pursuing for the older population considering the challenges they may face with transportation to the clinic setting and their increased risk for serious illness if exposed to infections such as COVID-19. The COVID-19 pandemic has brought to light the need for reliable, safe, and effective treatments that can be utilized in the safety of patients’ homes and should therefore be considered as an option for older adults. Issues such as mobility and cognitive decline could pose some complicating factors, but with the help of a well-trained family member or caregiver, home phototherapy could be a viable option that improves accessibility for older patients. Future research opportunities include further examination of the slower but ultimately equivalent response to phototherapy in the older population, the influence of photosensitizing medications on phototherapy effects, and the impact of phototherapy on utilization of immunosuppressive pharmaceuticals in older adults.

Identifying safe, effective, and affordable evidence-based dermatologic treatments for older adults can be challenging because of age-related changes in the skin, comorbidities, polypharmacy, mobility issues, and cognitive changes. Phototherapy has been shown to be an effective nonpharmacologic treatment option for multiple challenging dermatologic conditions^1-8; however, few studies have specifically examined its effectiveness in older adults. The challenge for older patients with psoriasis and dermatitis is that the conditions can be difficult to control and often require multiple treatment modalities.^9,10 Patients with psoriasis also have a higher risk for diabetes, dyslipidemia, and cardiovascular disease compared to other older patients,^11,12 which poses treatment challenges and makes nonpharmacologic treatments even more appealing.

Recent studies show that phototherapy can help decrease the use of dermatologic medications. Foerster and colleagues² found that adults with psoriasis who were treated with phototherapy significantly decreased their use of topical steroids (24.5% fewer patients required steroid creams and 31.1% fewer patients required psoriasis-specific topicals)(P<.01) while their use of non–psoriasis-specific medications did not change. Click and colleagues¹³ identified a decrease in medication costs, health care utilization, and risk for immunosuppression in patients treated with phototherapy when compared to those treated with biologics and apremilast. Methotrexate is a common dermatologic medication that is highly associated with increased risks in elderly patients because of impaired immune system function and the presence of comorbidities (eg, kidney disease, obesity, diabetes, fatty liver),¹⁴ which increase in prevalence with age. Combining phototherapy with methotrexate can substantially decrease the amount of methotrexate needed to achieve disease control,¹⁵ thereby decreasing the methotrexate-associated risks. Findings from these studies suggest that a safe, effective, cost-effective, and well-tolerated nonpharmacologic alternative, such as phototherapy, is highly desirable and should be optimized. Unfortunately, most studies that report the effectiveness of phototherapy are in younger populations.

This retrospective study aimed to (1) identify the most common dermatologic conditions treated with phototherapy in older adults, (2) examine the effectiveness and safety of phototherapy in older adults, and (3) compare the outcomes with 2 similar studies in the United Kingdom¹⁶ and Turkey.¹⁷

Methods

Design, Setting, Sample, and Statistical Analysis
The institutional review boards of Kaiser Permanente Washington Health Research Institute, Seattle, and the University of Washington, Seattle, approved this study. It was conducted in a large US multispecialty health care system (Group Health, Seattle, Washington [now Kaiser Permanente Washington]) serving approximately 600,000 patients, using billing records to identify all patients treated with phototherapy between January 1, 2015, and December 31, 2015, all who received narrowband UVB (NB-UVB) phototherapy. All adults 65 years and older who received phototherapy treatment during the 12-month study period were included. Patients were included regardless of comorbidities and other dermatologic treatments to maintain as much uniformity as possible between the present study and 2 prior studies examining phototherapy in older adult populations in the United Kingdom¹⁶ and Turkey.¹⁷ Demographic and clinical factors were presented using frequencies (percentages) or means and medians as appropriate. Comparisons of dermatologic conditions and clearance levels used a Fisher exact test. The number of phototherapy treatments to clearance and total number of treatments were compared between groups of patients using independent sample t tests.

Phototherapy Protocol
All patients received treatments administered by specially trained phototherapy nurses using a Daavlin UV Series (The Daavlin Company) or an Ultralite unit (Ultralite Enterprises, Inc), both with 48 lamps. All phototherapy nurses had been previously trained to provide treatments based on standardized protocols (Table 1) and to determine the patient’s level of disease clearance using a high to low clearance scale (Table 2). Daavlin’s treatment protocols were built into the software that accompanied the units and were developed based on the American Academy of Dermatology guidelines. The starting dose for an individual patient was determined based on the estimated minimal erythema dose for each phototype. If the patient was using photosensitizing medications, then the protocol guided the nurse to start the patient at a lower dose appropriate for their phototype. Patients with vitiligo were treated with the same starting and escalation doses as patients with Fitzpatrick phototype I because of the assumption that their vitiliginous skin had an increased risk for photosensitivity. A more recent review of the evidence has indicated that this assumption was overly conservative,¹⁸ and Kaiser Permanente Washington’s vitiligo protocol has been adjusted.

Results

Patients
Billing records identified 229 total patients who received phototherapy in 2015, of whom 52 (22.7%) were at least 65 years old. The median age was 70 years (range, 65–91 years). Twenty-nine (56%) were men and 35 (67%) had previously received phototherapy treatments.

Dermatologic Conditions Treated With Phototherapy
Our primary aim was to identify the most common dermatologic conditions treated with phototherapy in older adults. Psoriasis and dermatitis were the most common conditions treated in the sample (50% [26/52] and 21% [11/52], respectively), with mycosis fungoides being the third most common (10% [5/52]) and vitiligo tied with prurigo nodularis as fourth most common (6% [3/52])(Figure 1).

Effectiveness and Safety of Phototherapy
Our secondary aim was to examine the effectiveness and safety of phototherapy in older adults. Phototherapy was effective in this population, with 50 of 52 patients (96%) achieving a high or medium level of clearance. The degree of clearance for each of the dermatologic conditions is shown in Figure 2. Psoriasis and dermatitis achieved high clearance rates in 81% (21/26) and 82% (9/11) of patients, respectively. Overall, conditions did not have significant differences in clearances rates (Fisher exact test, P=.10). On average, it took patients 33 treatments to achieve medium or high rates of clearance. Psoriasis cleared more quickly, with an average of 30.4 treatments vs 36.1 treatments for other conditions, but the difference was not significant (t test, P=.26). Patients received an average of 98 total phototherapy treatments; the median number of treatments was 81 due to many being on maintenance therapy over several months. There was no relationship between a history of treatment with phototherapy and the total number of treatments needed to achieve clearance (t test, P=.40), but interestingly, those who had a history of phototherapy took approximately 5 more treatments to achieve clearance. The present study found that a slightly larger number of men were being treated for psoriasis (15 men vs 11 women), but there was no significant difference in response rate based on gender.

Comment

Our study found that 94% of patients with psoriasis achieved clearance with an average of 30.4 treatments, which is comparable to the reported 91% response rate with an average of 30 treatments in the United Kingdom.¹⁶ The other similar study in Turkey¹⁷ reported 73.7% of psoriasis patients achieved a 75% or more improvement from baseline with an average of 42 treatments, which may reflect underlying differences in regional skin type. Of note, the scatter chart (Figure 3) shows that several patients in the present study’s analysis are listed as not clear, but many of those patients had low treatment numbers below the mean time to clearance. Thus, the present study’s response rate may have been underestimated.

In the general population, studies show that psoriasis treated with standardized phototherapy protocols typically clears with an average of 20.6 treatments.²¹ The levels of clearance were similar in our study’s older population, but more treatments were required to achieve those results, with an average of 10 more treatments needed (an additional 3.3 weeks). Similar results were found in this sample for dermatitis and mycosis fungoides, indicating comparable clearance rates and levels but a need for more treatments to achieve similar results compared to the general population.

Additionally, in the current study more patients experienced grade 1 (mild) erythema (46%) and grade 2 erythema (25%) at some point in their treatment compared with the United Kingdom¹⁶ (1.89%) and Turkey¹⁷ (35%) studies, though these side effects did not impact the clearance rate. Interestingly, the current study’s scatter chart (Figure 3) illustrates that this side effect did not seem to increase with aging in this population. If anything, the erythema response was more prevalent in the median or younger patients in the sample. Erythema may have been due to the frequent use of photosensitizing medications in older adults in the United States, some of which typically get discontinued in patients 75 years and older (eg, statins). Other potential causes might include the use of phototype vs minimal erythema dose–driven protocols, the standard utilization of protocols originally designed for psoriasis vs other condition-specific protocols, missed treatments leading to increased sensitivity, or possibly shielding mishaps (eg, not wearing a prescribed face shield). Given the number of potential causes and the possibility of overlapping factors, careful analysis is important. With NB-UVB phototherapy, near-erythemogenic doses are optimal to achieve effective treatments, but this delicate balance may be more problematic for older adults. Future studies are needed to fully determine the factors at play for this population. In the interim, it is important for phototherapy-trained nurses to consider this risk carefully in the older population. They must follow the prescribed protocols that guide them to query patients about their responses to the prior treatment (eg, erythema, tenderness, itching), photosensitizing medications, missed treatments, and placement of shielding, and then adjust the treatment dosing accordingly.

Limitations
This study had several limitations. Although clinical outcomes were recorded prospectively, the analysis was retrospective, unblinded, and not placebo controlled. It was conducted in a single organization (Group Health [now Kaiser Permanente Washington]) but did analyze data from 4 medical centers in different cities with diverse demographics and a variety of nursing staff providing the treatments. Although the vitiligo treatment protocol likely slowed the response rate for those patients with vitiligo, the numbers were small (ie, only 3 of 52 patients), so the researchers chose to include them in the current study. The sample population was relatively small, but when these data are evaluated alongside the studies in the United Kingdom¹⁶ and Turkey,¹⁷ they show a consistent picture illustrating the effectiveness and safety of phototherapy in the older population. Further epidemiologic studies could be helpful to further describe the usefulness of this modality compared with other treatments for a variety of dermatoses in this age group. Supplementary analysis specifically examining the relationship between the number and type of photosensitizing medications, frequency of erythema, and time to clearance also could be useful.

Conclusion

Older adults with a variety of dermatoses respond well to phototherapy and should have the opportunity to use it, particularly considering the potential for increased complications and costs from other treatment modalities, such as commonly used immunosuppressive pharmaceuticals. However, the current study and the comparison studies indicate that it is important to carefully consider the slower clearance rates and the potential risk for increased erythema in this population and adjust patient education and treatment dosing accordingly.

Unfortunately, many dermatology centers do not offer phototherapy because of infrastructure limitations such as space and specially trained nursing staff. Increasing accessibility of phototherapy for older adults through home treatments may be an alternative, given its effectiveness in the general population.^22,23 In addition, home phototherapy may be worth pursuing for the older population considering the challenges they may face with transportation to the clinic setting and their increased risk for serious illness if exposed to infections such as COVID-19. The COVID-19 pandemic has brought to light the need for reliable, safe, and effective treatments that can be utilized in the safety of patients’ homes and should therefore be considered as an option for older adults. Issues such as mobility and cognitive decline could pose some complicating factors, but with the help of a well-trained family member or caregiver, home phototherapy could be a viable option that improves accessibility for older patients. Future research opportunities include further examination of the slower but ultimately equivalent response to phototherapy in the older population, the influence of photosensitizing medications on phototherapy effects, and the impact of phototherapy on utilization of immunosuppressive pharmaceuticals in older adults.