Nephrology

The Food and Drug Administration has approved canagliflozin (Invokana) for the treatment of diabetic kidney disease and for reduction of the risk of hospitalization for heart failure in patients with type 2 diabetes and diabetic kidney disease, which makes it the first drug indicated for diabetic kidney disease treatment in 20 years.

FDA approval, which was announced in a press release by Janssen, the drug’s manufacturer, is based on results from the phase 3 CREDENCE trial. In that study patients with type 2 diabetes and chronic diabetic kidney disease received either 100 mg canagliflozin or placebo. Patients who received canagliflozin experienced a 30% reduction in the risk of the primary composite endpoint, which included end-stage kidney disease, doubling of serum creatinine, and renal or cardiovascular death. The risk of secondary outcomes were also reduced in patients receiving canagliflozin, including a 39% reduction in the risk of hospitalization for heart failure.

The most common adverse events associated with canagliflozin, according to the label, are female genital mycotic infections, urinary tract infection, and increased urination. Serious adverse events associated with canagliflozin include ketoacidosis, kidney problems, serious urinary tract infections, hypoglycemia, necrotizing fasciitis, serious allergic reaction, and bone fractures.

“The real battle to turn the tide on kidney disease is in early detection and slowing its progression so that patients stay healthier and fewer patients reach kidney failure,” LaVerne A. Burton, president and CEO of the American Kidney Fund, said in the press release. “We are so grateful that advances in kidney disease research are producing treatment options that help to slow the progression of diabetic kidney disease and reduce the risk of hospitalization for heart failure.”

Find the full press release on the Janssen website.

[email protected]

The Food and Drug Administration has approved canagliflozin (Invokana) for the treatment of diabetic kidney disease and for reduction of the risk of hospitalization for heart failure in patients with type 2 diabetes and diabetic kidney disease, which makes it the first drug indicated for diabetic kidney disease treatment in 20 years.

FDA approval, which was announced in a press release by Janssen, the drug’s manufacturer, is based on results from the phase 3 CREDENCE trial. In that study patients with type 2 diabetes and chronic diabetic kidney disease received either 100 mg canagliflozin or placebo. Patients who received canagliflozin experienced a 30% reduction in the risk of the primary composite endpoint, which included end-stage kidney disease, doubling of serum creatinine, and renal or cardiovascular death. The risk of secondary outcomes were also reduced in patients receiving canagliflozin, including a 39% reduction in the risk of hospitalization for heart failure.

The most common adverse events associated with canagliflozin, according to the label, are female genital mycotic infections, urinary tract infection, and increased urination. Serious adverse events associated with canagliflozin include ketoacidosis, kidney problems, serious urinary tract infections, hypoglycemia, necrotizing fasciitis, serious allergic reaction, and bone fractures.

“The real battle to turn the tide on kidney disease is in early detection and slowing its progression so that patients stay healthier and fewer patients reach kidney failure,” LaVerne A. Burton, president and CEO of the American Kidney Fund, said in the press release. “We are so grateful that advances in kidney disease research are producing treatment options that help to slow the progression of diabetic kidney disease and reduce the risk of hospitalization for heart failure.”

Find the full press release on the Janssen website.

[email protected]

The Food and Drug Administration has approved canagliflozin (Invokana) for the treatment of diabetic kidney disease and for reduction of the risk of hospitalization for heart failure in patients with type 2 diabetes and diabetic kidney disease, which makes it the first drug indicated for diabetic kidney disease treatment in 20 years.

FDA approval, which was announced in a press release by Janssen, the drug’s manufacturer, is based on results from the phase 3 CREDENCE trial. In that study patients with type 2 diabetes and chronic diabetic kidney disease received either 100 mg canagliflozin or placebo. Patients who received canagliflozin experienced a 30% reduction in the risk of the primary composite endpoint, which included end-stage kidney disease, doubling of serum creatinine, and renal or cardiovascular death. The risk of secondary outcomes were also reduced in patients receiving canagliflozin, including a 39% reduction in the risk of hospitalization for heart failure.

The most common adverse events associated with canagliflozin, according to the label, are female genital mycotic infections, urinary tract infection, and increased urination. Serious adverse events associated with canagliflozin include ketoacidosis, kidney problems, serious urinary tract infections, hypoglycemia, necrotizing fasciitis, serious allergic reaction, and bone fractures.

“The real battle to turn the tide on kidney disease is in early detection and slowing its progression so that patients stay healthier and fewer patients reach kidney failure,” LaVerne A. Burton, president and CEO of the American Kidney Fund, said in the press release. “We are so grateful that advances in kidney disease research are producing treatment options that help to slow the progression of diabetic kidney disease and reduce the risk of hospitalization for heart failure.”

Find the full press release on the Janssen website.

[email protected]

Pregnant women should be screened for asymptomatic bacteriuria using urine culture because the benefit of reducing pyelonephritis during pregnancy slightly but significantly outweighs the risks of maternal and fetal antibiotic exposure, according to new recommendations set forth by the United States Preventive Services Task Force (USPSTF).

toeytoey2530/Thinkstock

However, the investigating committee reported, there is evidence against screening nonpregnant women and adult men. In fact, the committee found “adequate” evidence of potential harm associated with treating asymptomatic bacteriuria in adults of both sexes, including adverse effects of antibiotics and on the microbiome.

The new document downgrades from A to B the group’s prior recommendation that urine culture screening for asymptomatic bacteriuria should be performed among pregnant women at 12-16 weeks’ gestation or at their first prenatal visit. The USPSTF recommendation to not screen nonpregnant adults retained its D rating, Jerome A. Leis, MD and Christine Soong, MD said in an accompanying editorial.

“Not screening or treating asymptomatic bacteriuria in this population has long been an ironclad recommendation endorsed by the Infectious Diseases Society of America, as well as numerous professional societies as part of the Choosing Wisely campaign,” wrote Dr. Leis of Sunnybrook Health Sciences Centre, Toronto, and Dr. Soong of the University of Toronto. “Restating this steadfast and pervasive recommendation may seem unremarkable and almost pedantic, yet it remains stubbornly disregarded by clinicians across multiple settings.”

The new recommendations were based on a review of 19 studies involving almost 8,500 pregnant and nonpregnant women, as well as a small number of adult men. Most were carried out in the 1960s or 1970s. The most recent ones were published in 2002 and 2015. The dearth of more recent data may have limited some conclusions and certainly highlighted the need for more research, said Jillian T. Henderson, PhD, chair of the committee assigned to investigate the evidence.

“Few studies of asymptomatic bacteriuria screening or treatment in pregnant populations have been conducted in the past 40 years,” wrote Dr. Henderson of Kaiser Permanente Northwest, Portland, and associates. “Historical evidence established asymptomatic bacteriuria screening and treatment as standard obstetric practice in the United States.” But these trials typically were less rigorous than modern studies, and the results are out of touch with modern clinical settings and treatment protocols, the team noted.

Additionally, Dr. Henderson and coauthors said, rates of pyelonephritis were about 10 times higher then than they are now. In the more recent studies, pyelonephritis rates in control groups were 2.2% and 2.5%; in most of the older studies, control group rates ranged from 33% to 36%.

In commissioning the investigation, the task force looked at the following four questions:

Does screening improve health outcomes?

Neither of two studies involving 5,289 women, one from Spain and one from Turkey, addressed this question in nonpregnant women; however, studies that looked at pregnant women generally found that screening did reduce the risk of pyelonephritis by about 70%. The investigators cautioned that these studies were out of date and perhaps methodologically flawed.

The only study that looked at newborn outcomes found no difference in birth weights or premature births between the screened and unscreened cohorts.

No study examined this question in nonpregnant women or men.
 

What are the harms of such screening?

A single study of 372 pregnant women described potential prenatal and perinatal harms associated with screening and treatment. It found a slight increase in congenital abnormalities in the screened cohort (1.6%), compared with those who were not screened (1.1%). However, those who were not screened were presumably not prescribed antibiotics.

Does treatment of screening-detected asymptomatic bacteriuria improve health outcomes?

Twelve trials of pregnant women (2,377) addressed this issue. All but two were conducted in the 1960s and 1970s. Treatment varied widely; sulfonamides were the most common, including the now discarded sulfamethazine and sulfadimethoxine. Dosages and duration of treatment also were considerably higher and longer than current practice.

In all but one study, there were higher rates of pyelonephritis in the control group. A pooled risk analysis indicated that treatment reduced the risk of pyelonephritis by nearly 80% (relative risk, 0.24).

Seven studies found higher rates of low birth weight in infants born to mothers who were treated, but two studies reported a significant reduction in the risk of low birth weight.

Among the six trials that examined perinatal mortality, none found significant associations with treatment.

Five studies examined treatment in nonpregnant women with screening-detected asymptomatic bacteriuria, and one included men as well. Of the four that reported the rate of symptomatic infection or pyelonephritis, none found a significant difference between treatment and control groups. The single study that included men also found no significant difference between treatment and control groups.

Among the three studies that focused on older adults, there also were no significant between-group differences in outcomes.

What harms are associated with treatment of screening-detected asymptomatic bacteriuria?

Seven studies comprised pregnant women. Five reported congenital malformations in the intervention and control groups. Overall, there were very few cases of malformations, with more – although not significantly more – in the control groups.

Evidence related to other infant and maternal harms was “sparsely and inconsistently reported,” Dr. Henderson and coauthors noted, “and there was a lack of evidence on long-term neonatal outcomes after antibiotic treatment of asymptomatic bacteriuria in pregnancy.”

Two studies listed maternal adverse events associated with different treatments including vaginitis and diarrhea with ampicillin and rashes and nausea with nalidixic acid.

In terms of nonpregnant women and men, four studies reported adverse events. None occurred with nitrofurantoin or trimethoprim treatment; however, one study that included daily treatment with ofloxacin noted that 6% withdrew because of adverse events – vertigo and gastrointestinal symptoms.

Treatments didn’t affect hematocrit, bilirubin, serum urea, or nitrogen, although some studies found a slight reduction in serum creatinine.

Although there’s a need for additional research into this question, the new recommendations provide a good reason to further reduce unnecessary antibiotic exposure, Lindsey E. Nicolle, MD, wrote in a second commentary.

These updated recommendations “contribute to the evolution of management of asymptomatic bacteriuria in healthy women,” wrote Dr. Nicolle of the University of Manitoba, Winnipeg. “However, questions remain about the risks and benefits of universal screening for and treatment of asymptomatic bacteriuria in pregnant women in the context of current clinical practice. The effects of changes in fetal-maternal care, of low- compared with high-risk pregnancies, and of health care access need to be understood. In the short term, application of current diagnostic recommendations for identification of persistent symptomatic bacteriuria with a second urine culture may provide an immediate opportunity to limit unnecessary antimicrobial use for some pregnant women.”

No conflicts of interest were reported by the USPSTF authors, nor by Dr. Leis, Dr. Soong, or Dr. Nicolle. The USPSTF report was funded by the Agency for Healthcare Research and Quality.
 

SOURCES: U.S. Preventive Services Task Force. JAMA. 2019;322(12):1188-94; Henderson JT et al. JAMA. 2019;322(12):1195-205; Leis JA and Soong C. JAMA. 2019. doi: 10.1001/jamainternmed.2019.4515; Nicolle LE. JAMA. 2019;322(12):1152-4.

Pregnant women should be screened for asymptomatic bacteriuria using urine culture because the benefit of reducing pyelonephritis during pregnancy slightly but significantly outweighs the risks of maternal and fetal antibiotic exposure, according to new recommendations set forth by the United States Preventive Services Task Force (USPSTF).

toeytoey2530/Thinkstock

However, the investigating committee reported, there is evidence against screening nonpregnant women and adult men. In fact, the committee found “adequate” evidence of potential harm associated with treating asymptomatic bacteriuria in adults of both sexes, including adverse effects of antibiotics and on the microbiome.

The new document downgrades from A to B the group’s prior recommendation that urine culture screening for asymptomatic bacteriuria should be performed among pregnant women at 12-16 weeks’ gestation or at their first prenatal visit. The USPSTF recommendation to not screen nonpregnant adults retained its D rating, Jerome A. Leis, MD and Christine Soong, MD said in an accompanying editorial.

“Not screening or treating asymptomatic bacteriuria in this population has long been an ironclad recommendation endorsed by the Infectious Diseases Society of America, as well as numerous professional societies as part of the Choosing Wisely campaign,” wrote Dr. Leis of Sunnybrook Health Sciences Centre, Toronto, and Dr. Soong of the University of Toronto. “Restating this steadfast and pervasive recommendation may seem unremarkable and almost pedantic, yet it remains stubbornly disregarded by clinicians across multiple settings.”

The new recommendations were based on a review of 19 studies involving almost 8,500 pregnant and nonpregnant women, as well as a small number of adult men. Most were carried out in the 1960s or 1970s. The most recent ones were published in 2002 and 2015. The dearth of more recent data may have limited some conclusions and certainly highlighted the need for more research, said Jillian T. Henderson, PhD, chair of the committee assigned to investigate the evidence.

“Few studies of asymptomatic bacteriuria screening or treatment in pregnant populations have been conducted in the past 40 years,” wrote Dr. Henderson of Kaiser Permanente Northwest, Portland, and associates. “Historical evidence established asymptomatic bacteriuria screening and treatment as standard obstetric practice in the United States.” But these trials typically were less rigorous than modern studies, and the results are out of touch with modern clinical settings and treatment protocols, the team noted.

Additionally, Dr. Henderson and coauthors said, rates of pyelonephritis were about 10 times higher then than they are now. In the more recent studies, pyelonephritis rates in control groups were 2.2% and 2.5%; in most of the older studies, control group rates ranged from 33% to 36%.

In commissioning the investigation, the task force looked at the following four questions:

Does screening improve health outcomes?

Neither of two studies involving 5,289 women, one from Spain and one from Turkey, addressed this question in nonpregnant women; however, studies that looked at pregnant women generally found that screening did reduce the risk of pyelonephritis by about 70%. The investigators cautioned that these studies were out of date and perhaps methodologically flawed.

The only study that looked at newborn outcomes found no difference in birth weights or premature births between the screened and unscreened cohorts.

No study examined this question in nonpregnant women or men.
 

What are the harms of such screening?

A single study of 372 pregnant women described potential prenatal and perinatal harms associated with screening and treatment. It found a slight increase in congenital abnormalities in the screened cohort (1.6%), compared with those who were not screened (1.1%). However, those who were not screened were presumably not prescribed antibiotics.

Does treatment of screening-detected asymptomatic bacteriuria improve health outcomes?

Twelve trials of pregnant women (2,377) addressed this issue. All but two were conducted in the 1960s and 1970s. Treatment varied widely; sulfonamides were the most common, including the now discarded sulfamethazine and sulfadimethoxine. Dosages and duration of treatment also were considerably higher and longer than current practice.

In all but one study, there were higher rates of pyelonephritis in the control group. A pooled risk analysis indicated that treatment reduced the risk of pyelonephritis by nearly 80% (relative risk, 0.24).

Seven studies found higher rates of low birth weight in infants born to mothers who were treated, but two studies reported a significant reduction in the risk of low birth weight.

Among the six trials that examined perinatal mortality, none found significant associations with treatment.

Five studies examined treatment in nonpregnant women with screening-detected asymptomatic bacteriuria, and one included men as well. Of the four that reported the rate of symptomatic infection or pyelonephritis, none found a significant difference between treatment and control groups. The single study that included men also found no significant difference between treatment and control groups.

Among the three studies that focused on older adults, there also were no significant between-group differences in outcomes.

What harms are associated with treatment of screening-detected asymptomatic bacteriuria?

Seven studies comprised pregnant women. Five reported congenital malformations in the intervention and control groups. Overall, there were very few cases of malformations, with more – although not significantly more – in the control groups.

Evidence related to other infant and maternal harms was “sparsely and inconsistently reported,” Dr. Henderson and coauthors noted, “and there was a lack of evidence on long-term neonatal outcomes after antibiotic treatment of asymptomatic bacteriuria in pregnancy.”

Two studies listed maternal adverse events associated with different treatments including vaginitis and diarrhea with ampicillin and rashes and nausea with nalidixic acid.

In terms of nonpregnant women and men, four studies reported adverse events. None occurred with nitrofurantoin or trimethoprim treatment; however, one study that included daily treatment with ofloxacin noted that 6% withdrew because of adverse events – vertigo and gastrointestinal symptoms.

Treatments didn’t affect hematocrit, bilirubin, serum urea, or nitrogen, although some studies found a slight reduction in serum creatinine.

Although there’s a need for additional research into this question, the new recommendations provide a good reason to further reduce unnecessary antibiotic exposure, Lindsey E. Nicolle, MD, wrote in a second commentary.

These updated recommendations “contribute to the evolution of management of asymptomatic bacteriuria in healthy women,” wrote Dr. Nicolle of the University of Manitoba, Winnipeg. “However, questions remain about the risks and benefits of universal screening for and treatment of asymptomatic bacteriuria in pregnant women in the context of current clinical practice. The effects of changes in fetal-maternal care, of low- compared with high-risk pregnancies, and of health care access need to be understood. In the short term, application of current diagnostic recommendations for identification of persistent symptomatic bacteriuria with a second urine culture may provide an immediate opportunity to limit unnecessary antimicrobial use for some pregnant women.”

No conflicts of interest were reported by the USPSTF authors, nor by Dr. Leis, Dr. Soong, or Dr. Nicolle. The USPSTF report was funded by the Agency for Healthcare Research and Quality.
 

SOURCES: U.S. Preventive Services Task Force. JAMA. 2019;322(12):1188-94; Henderson JT et al. JAMA. 2019;322(12):1195-205; Leis JA and Soong C. JAMA. 2019. doi: 10.1001/jamainternmed.2019.4515; Nicolle LE. JAMA. 2019;322(12):1152-4.

Pregnant women should be screened for asymptomatic bacteriuria using urine culture because the benefit of reducing pyelonephritis during pregnancy slightly but significantly outweighs the risks of maternal and fetal antibiotic exposure, according to new recommendations set forth by the United States Preventive Services Task Force (USPSTF).

toeytoey2530/Thinkstock

However, the investigating committee reported, there is evidence against screening nonpregnant women and adult men. In fact, the committee found “adequate” evidence of potential harm associated with treating asymptomatic bacteriuria in adults of both sexes, including adverse effects of antibiotics and on the microbiome.

The new document downgrades from A to B the group’s prior recommendation that urine culture screening for asymptomatic bacteriuria should be performed among pregnant women at 12-16 weeks’ gestation or at their first prenatal visit. The USPSTF recommendation to not screen nonpregnant adults retained its D rating, Jerome A. Leis, MD and Christine Soong, MD said in an accompanying editorial.

“Not screening or treating asymptomatic bacteriuria in this population has long been an ironclad recommendation endorsed by the Infectious Diseases Society of America, as well as numerous professional societies as part of the Choosing Wisely campaign,” wrote Dr. Leis of Sunnybrook Health Sciences Centre, Toronto, and Dr. Soong of the University of Toronto. “Restating this steadfast and pervasive recommendation may seem unremarkable and almost pedantic, yet it remains stubbornly disregarded by clinicians across multiple settings.”

The new recommendations were based on a review of 19 studies involving almost 8,500 pregnant and nonpregnant women, as well as a small number of adult men. Most were carried out in the 1960s or 1970s. The most recent ones were published in 2002 and 2015. The dearth of more recent data may have limited some conclusions and certainly highlighted the need for more research, said Jillian T. Henderson, PhD, chair of the committee assigned to investigate the evidence.

“Few studies of asymptomatic bacteriuria screening or treatment in pregnant populations have been conducted in the past 40 years,” wrote Dr. Henderson of Kaiser Permanente Northwest, Portland, and associates. “Historical evidence established asymptomatic bacteriuria screening and treatment as standard obstetric practice in the United States.” But these trials typically were less rigorous than modern studies, and the results are out of touch with modern clinical settings and treatment protocols, the team noted.

Additionally, Dr. Henderson and coauthors said, rates of pyelonephritis were about 10 times higher then than they are now. In the more recent studies, pyelonephritis rates in control groups were 2.2% and 2.5%; in most of the older studies, control group rates ranged from 33% to 36%.

In commissioning the investigation, the task force looked at the following four questions:

Does screening improve health outcomes?

Neither of two studies involving 5,289 women, one from Spain and one from Turkey, addressed this question in nonpregnant women; however, studies that looked at pregnant women generally found that screening did reduce the risk of pyelonephritis by about 70%. The investigators cautioned that these studies were out of date and perhaps methodologically flawed.

The only study that looked at newborn outcomes found no difference in birth weights or premature births between the screened and unscreened cohorts.

No study examined this question in nonpregnant women or men.
 

What are the harms of such screening?

A single study of 372 pregnant women described potential prenatal and perinatal harms associated with screening and treatment. It found a slight increase in congenital abnormalities in the screened cohort (1.6%), compared with those who were not screened (1.1%). However, those who were not screened were presumably not prescribed antibiotics.

Does treatment of screening-detected asymptomatic bacteriuria improve health outcomes?

Twelve trials of pregnant women (2,377) addressed this issue. All but two were conducted in the 1960s and 1970s. Treatment varied widely; sulfonamides were the most common, including the now discarded sulfamethazine and sulfadimethoxine. Dosages and duration of treatment also were considerably higher and longer than current practice.

In all but one study, there were higher rates of pyelonephritis in the control group. A pooled risk analysis indicated that treatment reduced the risk of pyelonephritis by nearly 80% (relative risk, 0.24).

Seven studies found higher rates of low birth weight in infants born to mothers who were treated, but two studies reported a significant reduction in the risk of low birth weight.

Among the six trials that examined perinatal mortality, none found significant associations with treatment.

Five studies examined treatment in nonpregnant women with screening-detected asymptomatic bacteriuria, and one included men as well. Of the four that reported the rate of symptomatic infection or pyelonephritis, none found a significant difference between treatment and control groups. The single study that included men also found no significant difference between treatment and control groups.

Among the three studies that focused on older adults, there also were no significant between-group differences in outcomes.

What harms are associated with treatment of screening-detected asymptomatic bacteriuria?

Seven studies comprised pregnant women. Five reported congenital malformations in the intervention and control groups. Overall, there were very few cases of malformations, with more – although not significantly more – in the control groups.

Evidence related to other infant and maternal harms was “sparsely and inconsistently reported,” Dr. Henderson and coauthors noted, “and there was a lack of evidence on long-term neonatal outcomes after antibiotic treatment of asymptomatic bacteriuria in pregnancy.”

Two studies listed maternal adverse events associated with different treatments including vaginitis and diarrhea with ampicillin and rashes and nausea with nalidixic acid.

In terms of nonpregnant women and men, four studies reported adverse events. None occurred with nitrofurantoin or trimethoprim treatment; however, one study that included daily treatment with ofloxacin noted that 6% withdrew because of adverse events – vertigo and gastrointestinal symptoms.

Treatments didn’t affect hematocrit, bilirubin, serum urea, or nitrogen, although some studies found a slight reduction in serum creatinine.

Although there’s a need for additional research into this question, the new recommendations provide a good reason to further reduce unnecessary antibiotic exposure, Lindsey E. Nicolle, MD, wrote in a second commentary.

These updated recommendations “contribute to the evolution of management of asymptomatic bacteriuria in healthy women,” wrote Dr. Nicolle of the University of Manitoba, Winnipeg. “However, questions remain about the risks and benefits of universal screening for and treatment of asymptomatic bacteriuria in pregnant women in the context of current clinical practice. The effects of changes in fetal-maternal care, of low- compared with high-risk pregnancies, and of health care access need to be understood. In the short term, application of current diagnostic recommendations for identification of persistent symptomatic bacteriuria with a second urine culture may provide an immediate opportunity to limit unnecessary antimicrobial use for some pregnant women.”

No conflicts of interest were reported by the USPSTF authors, nor by Dr. Leis, Dr. Soong, or Dr. Nicolle. The USPSTF report was funded by the Agency for Healthcare Research and Quality.
 

SOURCES: U.S. Preventive Services Task Force. JAMA. 2019;322(12):1188-94; Henderson JT et al. JAMA. 2019;322(12):1195-205; Leis JA and Soong C. JAMA. 2019. doi: 10.1001/jamainternmed.2019.4515; Nicolle LE. JAMA. 2019;322(12):1152-4.

For non–status 1 patients with cirrhosis who are awaiting liver transplantation, type of renal dysfunction may be a key determinant of mortality risk, based on a retrospective analysis of more than 22,000 patients.

Risk of death was greatest for patients with acute on chronic kidney disease (AKI on CKD), followed by AKI alone, then CKD alone, reported lead author Giuseppe Cullaro, MD, of the University of California, San Francisco, and colleagues.

Although it is well known that renal dysfunction worsens outcomes among patients with liver cirrhosis, the impact of different types of kidney pathology on mortality risk has been minimally researched, the investigators wrote in Clinical Gastroenterology and Hepatology. “To date, studies evaluating the impact of renal dysfunction on prognosis in patients with cirrhosis have mostly focused on AKI.”

To learn more, the investigators performed a retrospective study involving acute, chronic, and acute on chronic kidney disease among patients with cirrhosis. They included data from 22,680 non–status 1 adults who were awaiting liver transplantation between 2007 and 2014, with at least 90 days on the wait list. Information was gathered from the Organ Procurement and Transplantation Network registry.

AKI was defined by fewer than 72 days of hemodialysis, or an increase in creatinine of at least 0.3 mg/dL or at least 50% in the last 7 days. CKD was identified by more than 72 days of hemodialysis, or an estimated glomerular filtration rate less than 60 mL/min/1.73 m² for 90 days with a final rate of at least 30 mL/min/1.73 m². Using these criteria, the researchers put patients into four possible categories: AKI on CKD, AKI, CKD, or normal renal function. The primary outcome was wait list mortality, which was defined as death, or removal from the wait list for illness. Follow-up started at the time of addition to the wait list and continued until transplant, removal from the wait list, or death.

Multivariate analysis, which accounted for final MELD-Na score and other confounders, showed that patients with AKI on CKD fared worst, with a 2.86-fold higher mortality risk (subhazard [SHR] ratio, 2.86) than that of patients with normal renal function. The mortality risk for acute on chronic kidney disease was followed closely by patients with AKI alone (SHR, 2.42), and more distantly by patients with CKD alone (SHR, 1.56). Further analysis showed that the disparity between mortality risks of each subgroup became more pronounced with increased MELD-Na score. In addition, evaluation of receiver operating characteristic curves for 6-month wait list mortality showed that the addition of renal function to MELD-Na score increased the accuracy of prognosis from an area under the curve of 0.71 to 0.80 (P less than .001).

“This suggests that incorporating the pattern of renal function could provide an opportunity to better prognosticate risk of mortality in the patients with cirrhosis who are the sickest,” the investigators concluded.

They also speculated about why outcomes may vary by type of kidney dysfunction.

“We suspect that those patients who experience AKI and AKI on CKD in our cohort likely had a triggering event – infection, bleeding, hypovolemia – that put these patients at greater risk for waitlist mortality,” the investigators wrote. “These events inherently carry more risk than stable nonliver-related elevations in serum creatinine that are seen in patients with CKD. Because of this heterogeneity of etiology in renal dysfunction in patients with cirrhosis, it is perhaps not surprising that unique renal function patterns variably impact mortality.”

The investigators noted that the findings from the study have “important implications for clinical practice,” and suggested that including type of renal dysfunction would have the most significant affect on accuracy of prognoses among patients at greatest risk of mortality.

The study was funded by a Paul B. Beeson Career Development Award and the National Institute of Diabetes and Digestive and Kidney Diseases. Dr. Verna disclosed relationships with Salix, Merck, and Gilead.

SOURCE: Cullaro et al. Clin Gastroenterol Hepatol. 2019 Feb 1. doi: 10.1016/j.cgh.2019.01.043.

For non–status 1 patients with cirrhosis who are awaiting liver transplantation, type of renal dysfunction may be a key determinant of mortality risk, based on a retrospective analysis of more than 22,000 patients.

Risk of death was greatest for patients with acute on chronic kidney disease (AKI on CKD), followed by AKI alone, then CKD alone, reported lead author Giuseppe Cullaro, MD, of the University of California, San Francisco, and colleagues.

Although it is well known that renal dysfunction worsens outcomes among patients with liver cirrhosis, the impact of different types of kidney pathology on mortality risk has been minimally researched, the investigators wrote in Clinical Gastroenterology and Hepatology. “To date, studies evaluating the impact of renal dysfunction on prognosis in patients with cirrhosis have mostly focused on AKI.”

To learn more, the investigators performed a retrospective study involving acute, chronic, and acute on chronic kidney disease among patients with cirrhosis. They included data from 22,680 non–status 1 adults who were awaiting liver transplantation between 2007 and 2014, with at least 90 days on the wait list. Information was gathered from the Organ Procurement and Transplantation Network registry.

AKI was defined by fewer than 72 days of hemodialysis, or an increase in creatinine of at least 0.3 mg/dL or at least 50% in the last 7 days. CKD was identified by more than 72 days of hemodialysis, or an estimated glomerular filtration rate less than 60 mL/min/1.73 m² for 90 days with a final rate of at least 30 mL/min/1.73 m². Using these criteria, the researchers put patients into four possible categories: AKI on CKD, AKI, CKD, or normal renal function. The primary outcome was wait list mortality, which was defined as death, or removal from the wait list for illness. Follow-up started at the time of addition to the wait list and continued until transplant, removal from the wait list, or death.

Multivariate analysis, which accounted for final MELD-Na score and other confounders, showed that patients with AKI on CKD fared worst, with a 2.86-fold higher mortality risk (subhazard [SHR] ratio, 2.86) than that of patients with normal renal function. The mortality risk for acute on chronic kidney disease was followed closely by patients with AKI alone (SHR, 2.42), and more distantly by patients with CKD alone (SHR, 1.56). Further analysis showed that the disparity between mortality risks of each subgroup became more pronounced with increased MELD-Na score. In addition, evaluation of receiver operating characteristic curves for 6-month wait list mortality showed that the addition of renal function to MELD-Na score increased the accuracy of prognosis from an area under the curve of 0.71 to 0.80 (P less than .001).

“This suggests that incorporating the pattern of renal function could provide an opportunity to better prognosticate risk of mortality in the patients with cirrhosis who are the sickest,” the investigators concluded.

They also speculated about why outcomes may vary by type of kidney dysfunction.

“We suspect that those patients who experience AKI and AKI on CKD in our cohort likely had a triggering event – infection, bleeding, hypovolemia – that put these patients at greater risk for waitlist mortality,” the investigators wrote. “These events inherently carry more risk than stable nonliver-related elevations in serum creatinine that are seen in patients with CKD. Because of this heterogeneity of etiology in renal dysfunction in patients with cirrhosis, it is perhaps not surprising that unique renal function patterns variably impact mortality.”

The investigators noted that the findings from the study have “important implications for clinical practice,” and suggested that including type of renal dysfunction would have the most significant affect on accuracy of prognoses among patients at greatest risk of mortality.

The study was funded by a Paul B. Beeson Career Development Award and the National Institute of Diabetes and Digestive and Kidney Diseases. Dr. Verna disclosed relationships with Salix, Merck, and Gilead.

SOURCE: Cullaro et al. Clin Gastroenterol Hepatol. 2019 Feb 1. doi: 10.1016/j.cgh.2019.01.043.

For non–status 1 patients with cirrhosis who are awaiting liver transplantation, type of renal dysfunction may be a key determinant of mortality risk, based on a retrospective analysis of more than 22,000 patients.

Risk of death was greatest for patients with acute on chronic kidney disease (AKI on CKD), followed by AKI alone, then CKD alone, reported lead author Giuseppe Cullaro, MD, of the University of California, San Francisco, and colleagues.

Although it is well known that renal dysfunction worsens outcomes among patients with liver cirrhosis, the impact of different types of kidney pathology on mortality risk has been minimally researched, the investigators wrote in Clinical Gastroenterology and Hepatology. “To date, studies evaluating the impact of renal dysfunction on prognosis in patients with cirrhosis have mostly focused on AKI.”

To learn more, the investigators performed a retrospective study involving acute, chronic, and acute on chronic kidney disease among patients with cirrhosis. They included data from 22,680 non–status 1 adults who were awaiting liver transplantation between 2007 and 2014, with at least 90 days on the wait list. Information was gathered from the Organ Procurement and Transplantation Network registry.

AKI was defined by fewer than 72 days of hemodialysis, or an increase in creatinine of at least 0.3 mg/dL or at least 50% in the last 7 days. CKD was identified by more than 72 days of hemodialysis, or an estimated glomerular filtration rate less than 60 mL/min/1.73 m² for 90 days with a final rate of at least 30 mL/min/1.73 m². Using these criteria, the researchers put patients into four possible categories: AKI on CKD, AKI, CKD, or normal renal function. The primary outcome was wait list mortality, which was defined as death, or removal from the wait list for illness. Follow-up started at the time of addition to the wait list and continued until transplant, removal from the wait list, or death.

Multivariate analysis, which accounted for final MELD-Na score and other confounders, showed that patients with AKI on CKD fared worst, with a 2.86-fold higher mortality risk (subhazard [SHR] ratio, 2.86) than that of patients with normal renal function. The mortality risk for acute on chronic kidney disease was followed closely by patients with AKI alone (SHR, 2.42), and more distantly by patients with CKD alone (SHR, 1.56). Further analysis showed that the disparity between mortality risks of each subgroup became more pronounced with increased MELD-Na score. In addition, evaluation of receiver operating characteristic curves for 6-month wait list mortality showed that the addition of renal function to MELD-Na score increased the accuracy of prognosis from an area under the curve of 0.71 to 0.80 (P less than .001).

“This suggests that incorporating the pattern of renal function could provide an opportunity to better prognosticate risk of mortality in the patients with cirrhosis who are the sickest,” the investigators concluded.

They also speculated about why outcomes may vary by type of kidney dysfunction.

“We suspect that those patients who experience AKI and AKI on CKD in our cohort likely had a triggering event – infection, bleeding, hypovolemia – that put these patients at greater risk for waitlist mortality,” the investigators wrote. “These events inherently carry more risk than stable nonliver-related elevations in serum creatinine that are seen in patients with CKD. Because of this heterogeneity of etiology in renal dysfunction in patients with cirrhosis, it is perhaps not surprising that unique renal function patterns variably impact mortality.”

The investigators noted that the findings from the study have “important implications for clinical practice,” and suggested that including type of renal dysfunction would have the most significant affect on accuracy of prognoses among patients at greatest risk of mortality.

The study was funded by a Paul B. Beeson Career Development Award and the National Institute of Diabetes and Digestive and Kidney Diseases. Dr. Verna disclosed relationships with Salix, Merck, and Gilead.

SOURCE: Cullaro et al. Clin Gastroenterol Hepatol. 2019 Feb 1. doi: 10.1016/j.cgh.2019.01.043.

Inhibition of the renin-angiotensin-aldosterone system with angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) is widely used in the treatment of heart failure, hypertension, chronic kidney disease, and coronary artery disease with left ventricular dysfunction.

See related article

In this issue, Momoniat et al¹ review the benefits of ACE inhibitors and ARBs and how to manage adverse effects. I would like to add some of my own observations.

ARE ACE INHIBITORS REALLY BETTER THAN ARBs?

ACE inhibitors have been the cornerstone of treatment for patients with heart failure with reduced ejection fraction (HFrEF), in whom their use is associated with reduced rates of morbidity and death.^2,3 The use of ARBs in these patients is also associated with decreased rates of morbidity and death^4,5; however, in early comparisons, ACE inhibitors were deemed more effective in decreasing the incidence of myocardial infarction, cardiovascular death, and all-cause mortality in patients with hypertension, diabetes, and increased cardiovascular risk,⁶ and all-cause mortality in patients with HFrEF.⁷

This presumed superiority of ACE inhibitors over ARBs was thought to be a result of a greater vasodilatory effect caused by inhibiting the degradation of bradykinin and leading to increased levels of nitric oxide and vasoactive prostaglandins.⁸ Another proposed explanation was that because ARBs block angiotensin II AT1 receptors but not AT2 receptors, the increased stimulation of markedly upregulated AT2 receptors in atheromatous plaques in response to elevated serum levels of angiotensin II was deleterious.⁶ Therefore, ACE inhibitors have been recommended as first-line therapy by most guidelines, whereas ARBs are recommended as second-line therapy, when patients are unable to tolerate ACE inhibitors.

Nevertheless, the much debated differences in outcomes between ACE inhibitors and ARBs do not seem to be real and may have originated from a generational gap in the trials.

The ACE inhibitor trials were performed a decade earlier than the ARB trials. Indirect comparisons of their respective placebo-controlled trials assumed that the placebo groups used for comparison in the 2 sets of trials were similar.^9,10 Actually, the rate of cardiovascular disease decreased nearly 50% between the decades of 1990 to 2000 and 2000 to 2010, the likely result of aggressive primary and secondary prevention strategies in clinical practice, including revascularization and lipid-lowering therapy.¹⁰

In fact, a meta-regression analysis showed that the differences between ACE inhibitors and ARBs compared with placebo were due to higher event rates in the placebo groups in the ACE inhibitor trials than in the ARB trials for the outcomes of death, cardiovascular death, and myocardial infarction.¹¹ Sensitivity analyses restricted to trials published after 2000 to control for this generational gap showed similar efficacy with ACE inhibitors vs placebo and with ARBs vs placebo for all clinical outcomes.¹¹ Moreover, recent studies have shown that ARBs produce a greater decrease in cardiovascular events than ACE inhibitors, especially in patients with established cardiovascular disease.^12,13

An advantage of ARBs over ACE inhibitors is fewer adverse effects: in general, ARBs are better tolerated than ACE inhibitors.¹⁴ There are also ethnic differences in the risks of adverse reactions to these medications. African Americans have a higher risk of developing angioedema with ACE inhibitors compared with the rest of the US population, and Chinese Americans have a higher risk than whites of developing cough with ACE inhibitors.^9,15

In my medical practice, I try to make sure patients with HFrEF, hypertension, chronic kidney disease, and coronary artery disease with left ventricular dysfunction receive an inhibitor of the renin-angiotensin-aldosterone system.

Which agent?

I prefer ARBs because patients tolerate them better. I continue ACE inhibitors in patients who are already taking them without adverse effects, and I change to ARBs in patients who later become unable to tolerate ACE inhibitors.

Most antihypertensive agents increase the risk of incident gout, except for calcium channel blockers and losartan.¹⁶ Losartan is the only ARB with a uricosuric effect, although a mild one,^17,18 due to inhibition of the urate transporter 1,¹⁹ and therefore I prefer to use it instead of other ARBs or ACE inhibitors in patients who have a concomitant diagnosis of gout.

Which combinations of agents?

The addition of beta-blockers and mineralocorticoid receptor blockers to ACE inhibitors or ARBs is associated with a further decrease in the mortality risk for patients with HFrEF,^20–22 but some patients cannot tolerate these combinations or optimized doses of these medications because of worsening hypotension or increased risk of developing acute kidney injury or hyperkalemia.

In most cases, I try not to combine ACE inhibitors with ARBs. This combination may be useful in nondiabetic patients with proteinuria refractory to maximum treatment with 1 class of these agents, but it is associated with an increased risk of hyperkalemia or acute kidney injury in patients with diabetic nephropathy without improving rates of the clinical outcomes of death or cardiovascular events.²³ I prefer adding a daily low dose of a mineralocorticoid receptor blocker to an ACE inhibitor or an ARB, which is more effective in controlling refractory proteinuria.²⁴ This regimen is associated with decreased rates of mortality, cardiovascular mortality, and hospitalization for heart failure in patients with HFrEF,²² although it can lead to a higher frequency of hyperkalemia,²⁵ and patients on it require frequent dietary education and monitoring of serum potassium.

I avoid combining direct renin inhibitors with ACE inhibitors or ARBs, since this combination has been contraindicated by the US Food and Drug Administration due to lack of reduction in target-organ damage and an associated increased risk of hypotension, hyperkalemia, and kidney failure, and a slight increase in the risk of stroke or death in patients with diabetic nephropathy.²⁶

Valsartan-sacubitril

Neprilysin is a membrane-bound endopeptidase that degrades vasoactive peptides, including B-type natriuretic peptide and atrial natriuretic peptide.²⁷ The combination of the ARB valsartan and the neprilysin inhibitor sacubitril is associated with a 20% further decrease in rates of cardiovascular mortality and hospitalization and a 16% decrease in total mortality for patients with HFrEF compared with an ACE inhibitor, although there can also be more hypotension and angioedema with the combination.^27,28

Very importantly, an ACE inhibitor cannot be used together with valsartan-sacubitril due to increased risk of angioedema and cough. I change ACE inhibitors or ARBs to valsartan-sacubitril in patients with HFrEF who still have symptoms of heart failure. Interestingly, a network meta-analysis showed that the combination of valsartan-sacubitril plus a mineralocorticoid receptor blocker and a beta-blocker resulted in the greatest mortality reduction in patients with HFrEF.⁷ A word of caution, though: one can also expect an increased risk of hypotension, hyperkalemia, and kidney failure.

Monitoring

It is crucial to monitor blood pressure, serum potassium, and renal function in patients receiving ACE inhibitors, ARBs, mineralocorticoid receptor blockers, valsartan-sacubitril, or combinations of these medications, particularly in elderly patients, who are more susceptible to complications. I use a multidisciplinary approach in my clinic: a patient educator, dietitian, pharmacist, and advanced practice nurse play key roles in educating and monitoring patients for the development of possible complications from this therapy or interactions with other medications.

A recent population-based cohort study found an association of ACE inhibitor use with a 14% relative increase in lung cancer incidence after 10 years of use, compared with ARBs,²⁹ but this may not represent a large absolute risk (calculated number needed to harm of 2,970 after 10 years of ACE inhibitor use) and should be balanced against the improvement in morbidity and mortality gained with use of an ACE inhibitor. Additional studies with long-term follow-up are needed to investigate this possible association.

TAKE-HOME POINTS

• Blockade of the renin-angiotensin-aldosterone system is a cornerstone in the therapy of cardiovascular disease.
• ARBs are as effective as ACE inhibitors and have a better tolerability profile.
• ACE inhibitors cause more angioedema in African Americans and more cough in Chinese Americans than in the rest of the population.
• ACE inhibitors and most ARBs (except for losartan) increase the risk of gout.
• The combination of beta-blockers and mineralocorticoid receptor blockers with ACE inhibitors or ARBs and, lately, the use of the valsartan-sacubitril combination have been increasingly beneficial for patients with HFrEF.

Inhibition of the renin-angiotensin-aldosterone system with angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) is widely used in the treatment of heart failure, hypertension, chronic kidney disease, and coronary artery disease with left ventricular dysfunction.

See related article

In this issue, Momoniat et al¹ review the benefits of ACE inhibitors and ARBs and how to manage adverse effects. I would like to add some of my own observations.

ARE ACE INHIBITORS REALLY BETTER THAN ARBs?

ACE inhibitors have been the cornerstone of treatment for patients with heart failure with reduced ejection fraction (HFrEF), in whom their use is associated with reduced rates of morbidity and death.^2,3 The use of ARBs in these patients is also associated with decreased rates of morbidity and death^4,5; however, in early comparisons, ACE inhibitors were deemed more effective in decreasing the incidence of myocardial infarction, cardiovascular death, and all-cause mortality in patients with hypertension, diabetes, and increased cardiovascular risk,⁶ and all-cause mortality in patients with HFrEF.⁷

This presumed superiority of ACE inhibitors over ARBs was thought to be a result of a greater vasodilatory effect caused by inhibiting the degradation of bradykinin and leading to increased levels of nitric oxide and vasoactive prostaglandins.⁸ Another proposed explanation was that because ARBs block angiotensin II AT1 receptors but not AT2 receptors, the increased stimulation of markedly upregulated AT2 receptors in atheromatous plaques in response to elevated serum levels of angiotensin II was deleterious.⁶ Therefore, ACE inhibitors have been recommended as first-line therapy by most guidelines, whereas ARBs are recommended as second-line therapy, when patients are unable to tolerate ACE inhibitors.

Nevertheless, the much debated differences in outcomes between ACE inhibitors and ARBs do not seem to be real and may have originated from a generational gap in the trials.

The ACE inhibitor trials were performed a decade earlier than the ARB trials. Indirect comparisons of their respective placebo-controlled trials assumed that the placebo groups used for comparison in the 2 sets of trials were similar.^9,10 Actually, the rate of cardiovascular disease decreased nearly 50% between the decades of 1990 to 2000 and 2000 to 2010, the likely result of aggressive primary and secondary prevention strategies in clinical practice, including revascularization and lipid-lowering therapy.¹⁰

In fact, a meta-regression analysis showed that the differences between ACE inhibitors and ARBs compared with placebo were due to higher event rates in the placebo groups in the ACE inhibitor trials than in the ARB trials for the outcomes of death, cardiovascular death, and myocardial infarction.¹¹ Sensitivity analyses restricted to trials published after 2000 to control for this generational gap showed similar efficacy with ACE inhibitors vs placebo and with ARBs vs placebo for all clinical outcomes.¹¹ Moreover, recent studies have shown that ARBs produce a greater decrease in cardiovascular events than ACE inhibitors, especially in patients with established cardiovascular disease.^12,13

An advantage of ARBs over ACE inhibitors is fewer adverse effects: in general, ARBs are better tolerated than ACE inhibitors.¹⁴ There are also ethnic differences in the risks of adverse reactions to these medications. African Americans have a higher risk of developing angioedema with ACE inhibitors compared with the rest of the US population, and Chinese Americans have a higher risk than whites of developing cough with ACE inhibitors.^9,15

In my medical practice, I try to make sure patients with HFrEF, hypertension, chronic kidney disease, and coronary artery disease with left ventricular dysfunction receive an inhibitor of the renin-angiotensin-aldosterone system.

Which agent?

I prefer ARBs because patients tolerate them better. I continue ACE inhibitors in patients who are already taking them without adverse effects, and I change to ARBs in patients who later become unable to tolerate ACE inhibitors.

Most antihypertensive agents increase the risk of incident gout, except for calcium channel blockers and losartan.¹⁶ Losartan is the only ARB with a uricosuric effect, although a mild one,^17,18 due to inhibition of the urate transporter 1,¹⁹ and therefore I prefer to use it instead of other ARBs or ACE inhibitors in patients who have a concomitant diagnosis of gout.

Which combinations of agents?

The addition of beta-blockers and mineralocorticoid receptor blockers to ACE inhibitors or ARBs is associated with a further decrease in the mortality risk for patients with HFrEF,^20–22 but some patients cannot tolerate these combinations or optimized doses of these medications because of worsening hypotension or increased risk of developing acute kidney injury or hyperkalemia.

In most cases, I try not to combine ACE inhibitors with ARBs. This combination may be useful in nondiabetic patients with proteinuria refractory to maximum treatment with 1 class of these agents, but it is associated with an increased risk of hyperkalemia or acute kidney injury in patients with diabetic nephropathy without improving rates of the clinical outcomes of death or cardiovascular events.²³ I prefer adding a daily low dose of a mineralocorticoid receptor blocker to an ACE inhibitor or an ARB, which is more effective in controlling refractory proteinuria.²⁴ This regimen is associated with decreased rates of mortality, cardiovascular mortality, and hospitalization for heart failure in patients with HFrEF,²² although it can lead to a higher frequency of hyperkalemia,²⁵ and patients on it require frequent dietary education and monitoring of serum potassium.

I avoid combining direct renin inhibitors with ACE inhibitors or ARBs, since this combination has been contraindicated by the US Food and Drug Administration due to lack of reduction in target-organ damage and an associated increased risk of hypotension, hyperkalemia, and kidney failure, and a slight increase in the risk of stroke or death in patients with diabetic nephropathy.²⁶

Valsartan-sacubitril

Neprilysin is a membrane-bound endopeptidase that degrades vasoactive peptides, including B-type natriuretic peptide and atrial natriuretic peptide.²⁷ The combination of the ARB valsartan and the neprilysin inhibitor sacubitril is associated with a 20% further decrease in rates of cardiovascular mortality and hospitalization and a 16% decrease in total mortality for patients with HFrEF compared with an ACE inhibitor, although there can also be more hypotension and angioedema with the combination.^27,28

Very importantly, an ACE inhibitor cannot be used together with valsartan-sacubitril due to increased risk of angioedema and cough. I change ACE inhibitors or ARBs to valsartan-sacubitril in patients with HFrEF who still have symptoms of heart failure. Interestingly, a network meta-analysis showed that the combination of valsartan-sacubitril plus a mineralocorticoid receptor blocker and a beta-blocker resulted in the greatest mortality reduction in patients with HFrEF.⁷ A word of caution, though: one can also expect an increased risk of hypotension, hyperkalemia, and kidney failure.

Monitoring

It is crucial to monitor blood pressure, serum potassium, and renal function in patients receiving ACE inhibitors, ARBs, mineralocorticoid receptor blockers, valsartan-sacubitril, or combinations of these medications, particularly in elderly patients, who are more susceptible to complications. I use a multidisciplinary approach in my clinic: a patient educator, dietitian, pharmacist, and advanced practice nurse play key roles in educating and monitoring patients for the development of possible complications from this therapy or interactions with other medications.

A recent population-based cohort study found an association of ACE inhibitor use with a 14% relative increase in lung cancer incidence after 10 years of use, compared with ARBs,²⁹ but this may not represent a large absolute risk (calculated number needed to harm of 2,970 after 10 years of ACE inhibitor use) and should be balanced against the improvement in morbidity and mortality gained with use of an ACE inhibitor. Additional studies with long-term follow-up are needed to investigate this possible association.

TAKE-HOME POINTS

• Blockade of the renin-angiotensin-aldosterone system is a cornerstone in the therapy of cardiovascular disease.
• ARBs are as effective as ACE inhibitors and have a better tolerability profile.
• ACE inhibitors cause more angioedema in African Americans and more cough in Chinese Americans than in the rest of the population.
• ACE inhibitors and most ARBs (except for losartan) increase the risk of gout.
• The combination of beta-blockers and mineralocorticoid receptor blockers with ACE inhibitors or ARBs and, lately, the use of the valsartan-sacubitril combination have been increasingly beneficial for patients with HFrEF.

Inhibition of the renin-angiotensin-aldosterone system with angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) is widely used in the treatment of heart failure, hypertension, chronic kidney disease, and coronary artery disease with left ventricular dysfunction.

See related article

In this issue, Momoniat et al¹ review the benefits of ACE inhibitors and ARBs and how to manage adverse effects. I would like to add some of my own observations.

ARE ACE INHIBITORS REALLY BETTER THAN ARBs?

ACE inhibitors have been the cornerstone of treatment for patients with heart failure with reduced ejection fraction (HFrEF), in whom their use is associated with reduced rates of morbidity and death.^2,3 The use of ARBs in these patients is also associated with decreased rates of morbidity and death^4,5; however, in early comparisons, ACE inhibitors were deemed more effective in decreasing the incidence of myocardial infarction, cardiovascular death, and all-cause mortality in patients with hypertension, diabetes, and increased cardiovascular risk,⁶ and all-cause mortality in patients with HFrEF.⁷

This presumed superiority of ACE inhibitors over ARBs was thought to be a result of a greater vasodilatory effect caused by inhibiting the degradation of bradykinin and leading to increased levels of nitric oxide and vasoactive prostaglandins.⁸ Another proposed explanation was that because ARBs block angiotensin II AT1 receptors but not AT2 receptors, the increased stimulation of markedly upregulated AT2 receptors in atheromatous plaques in response to elevated serum levels of angiotensin II was deleterious.⁶ Therefore, ACE inhibitors have been recommended as first-line therapy by most guidelines, whereas ARBs are recommended as second-line therapy, when patients are unable to tolerate ACE inhibitors.

Nevertheless, the much debated differences in outcomes between ACE inhibitors and ARBs do not seem to be real and may have originated from a generational gap in the trials.

The ACE inhibitor trials were performed a decade earlier than the ARB trials. Indirect comparisons of their respective placebo-controlled trials assumed that the placebo groups used for comparison in the 2 sets of trials were similar.^9,10 Actually, the rate of cardiovascular disease decreased nearly 50% between the decades of 1990 to 2000 and 2000 to 2010, the likely result of aggressive primary and secondary prevention strategies in clinical practice, including revascularization and lipid-lowering therapy.¹⁰

In fact, a meta-regression analysis showed that the differences between ACE inhibitors and ARBs compared with placebo were due to higher event rates in the placebo groups in the ACE inhibitor trials than in the ARB trials for the outcomes of death, cardiovascular death, and myocardial infarction.¹¹ Sensitivity analyses restricted to trials published after 2000 to control for this generational gap showed similar efficacy with ACE inhibitors vs placebo and with ARBs vs placebo for all clinical outcomes.¹¹ Moreover, recent studies have shown that ARBs produce a greater decrease in cardiovascular events than ACE inhibitors, especially in patients with established cardiovascular disease.^12,13

An advantage of ARBs over ACE inhibitors is fewer adverse effects: in general, ARBs are better tolerated than ACE inhibitors.¹⁴ There are also ethnic differences in the risks of adverse reactions to these medications. African Americans have a higher risk of developing angioedema with ACE inhibitors compared with the rest of the US population, and Chinese Americans have a higher risk than whites of developing cough with ACE inhibitors.^9,15

In my medical practice, I try to make sure patients with HFrEF, hypertension, chronic kidney disease, and coronary artery disease with left ventricular dysfunction receive an inhibitor of the renin-angiotensin-aldosterone system.

Which agent?

I prefer ARBs because patients tolerate them better. I continue ACE inhibitors in patients who are already taking them without adverse effects, and I change to ARBs in patients who later become unable to tolerate ACE inhibitors.

Most antihypertensive agents increase the risk of incident gout, except for calcium channel blockers and losartan.¹⁶ Losartan is the only ARB with a uricosuric effect, although a mild one,^17,18 due to inhibition of the urate transporter 1,¹⁹ and therefore I prefer to use it instead of other ARBs or ACE inhibitors in patients who have a concomitant diagnosis of gout.

Which combinations of agents?

The addition of beta-blockers and mineralocorticoid receptor blockers to ACE inhibitors or ARBs is associated with a further decrease in the mortality risk for patients with HFrEF,^20–22 but some patients cannot tolerate these combinations or optimized doses of these medications because of worsening hypotension or increased risk of developing acute kidney injury or hyperkalemia.

In most cases, I try not to combine ACE inhibitors with ARBs. This combination may be useful in nondiabetic patients with proteinuria refractory to maximum treatment with 1 class of these agents, but it is associated with an increased risk of hyperkalemia or acute kidney injury in patients with diabetic nephropathy without improving rates of the clinical outcomes of death or cardiovascular events.²³ I prefer adding a daily low dose of a mineralocorticoid receptor blocker to an ACE inhibitor or an ARB, which is more effective in controlling refractory proteinuria.²⁴ This regimen is associated with decreased rates of mortality, cardiovascular mortality, and hospitalization for heart failure in patients with HFrEF,²² although it can lead to a higher frequency of hyperkalemia,²⁵ and patients on it require frequent dietary education and monitoring of serum potassium.

I avoid combining direct renin inhibitors with ACE inhibitors or ARBs, since this combination has been contraindicated by the US Food and Drug Administration due to lack of reduction in target-organ damage and an associated increased risk of hypotension, hyperkalemia, and kidney failure, and a slight increase in the risk of stroke or death in patients with diabetic nephropathy.²⁶

Valsartan-sacubitril

Neprilysin is a membrane-bound endopeptidase that degrades vasoactive peptides, including B-type natriuretic peptide and atrial natriuretic peptide.²⁷ The combination of the ARB valsartan and the neprilysin inhibitor sacubitril is associated with a 20% further decrease in rates of cardiovascular mortality and hospitalization and a 16% decrease in total mortality for patients with HFrEF compared with an ACE inhibitor, although there can also be more hypotension and angioedema with the combination.^27,28

Very importantly, an ACE inhibitor cannot be used together with valsartan-sacubitril due to increased risk of angioedema and cough. I change ACE inhibitors or ARBs to valsartan-sacubitril in patients with HFrEF who still have symptoms of heart failure. Interestingly, a network meta-analysis showed that the combination of valsartan-sacubitril plus a mineralocorticoid receptor blocker and a beta-blocker resulted in the greatest mortality reduction in patients with HFrEF.⁷ A word of caution, though: one can also expect an increased risk of hypotension, hyperkalemia, and kidney failure.

Monitoring

It is crucial to monitor blood pressure, serum potassium, and renal function in patients receiving ACE inhibitors, ARBs, mineralocorticoid receptor blockers, valsartan-sacubitril, or combinations of these medications, particularly in elderly patients, who are more susceptible to complications. I use a multidisciplinary approach in my clinic: a patient educator, dietitian, pharmacist, and advanced practice nurse play key roles in educating and monitoring patients for the development of possible complications from this therapy or interactions with other medications.

A recent population-based cohort study found an association of ACE inhibitor use with a 14% relative increase in lung cancer incidence after 10 years of use, compared with ARBs,²⁹ but this may not represent a large absolute risk (calculated number needed to harm of 2,970 after 10 years of ACE inhibitor use) and should be balanced against the improvement in morbidity and mortality gained with use of an ACE inhibitor. Additional studies with long-term follow-up are needed to investigate this possible association.

TAKE-HOME POINTS

• Blockade of the renin-angiotensin-aldosterone system is a cornerstone in the therapy of cardiovascular disease.
• ARBs are as effective as ACE inhibitors and have a better tolerability profile.
• ACE inhibitors cause more angioedema in African Americans and more cough in Chinese Americans than in the rest of the population.
• ACE inhibitors and most ARBs (except for losartan) increase the risk of gout.
• The combination of beta-blockers and mineralocorticoid receptor blockers with ACE inhibitors or ARBs and, lately, the use of the valsartan-sacubitril combination have been increasingly beneficial for patients with HFrEF.

A highly active, water- and alcohol-soluble, basic pressor substance is formed when renin and renin-activator interact, for which we suggest the name “angiotonin.”

—Irvine H. Page and O.M. Helmer, 1940.¹

The renin-angiotensin-aldosterone system regulates salt and, in part, water homeostasis, and therefore blood pressure and fluid balance through its actions on the heart, kidneys, and blood vessels.² Drugs that target this system—angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs)—are used primarily to treat hypertension and also to treat chronic kidney disease and heart failure with reduced ejection fraction.

See related editorial

Controlling blood pressure is important, as hypertension increases the risk of myocardial infarction, cerebrovascular events, and progression of chronic kidney disease, which itself is a risk factor for cardiovascular disease. However, the benefit of these drugs is only partly due to their effect on blood pressure. They also reduce proteinuria, which is a graded risk factor for progression of kidney disease as well as morbidity and death from vascular events.³

Despite the benefits of ACE inhibitors and ARBs, concern about their adverse effects—especially hyperkalemia and a decline in renal function—has led to their underuse in patients likely to derive the greatest benefit.³

ACE INHIBITORS AND ARBs

ACE inhibitors, as their name indicates, inhibit conversion of angiotensin I to angiotensin II by ACE, resulting in vasodilation of the efferent arteriole and a drop in blood pressure. Inhibition of ACE, a kininase, also results in a rise in kinins. One of these, bradykinin, is associated with some of the side effects of this class of drugs such as cough, which affects 5% to 20% of patients.⁴ Elevation of bradykinin is also believed to account for ACE inhibitor-induced angioedema, an uncommon but potentially serious side effect. Kinins are also associated with desirable effects such as lowering blood pressure, increasing insulin sensitivity, and dilating blood vessels.

ARBs were developed as an alternative for patients unable to tolerate the adverse effects of ACE inhibitors. While ACE inhibitors reduce the activity of angiotensin II at both the AT1 and AT2 receptors, ARBs block only the AT1 receptors, thereby inhibiting their vasoconstricting activity on smooth muscle. ARBs also raise the levels of renin, angiotensin I, and angiotensin II as a result of feedback inhibition. Angiotensin II is associated with release of inflammatory mediators such as tumor necrosis factor alpha, cytokines, and chemokines, the consequences of which are also inhibited by ARBs, further preventing renal fibrosis and scarring from chronic inflammation.³

What is the evidence supporting the use of ACE inhibitors and ARBs?

ACE inhibitors and ARBs, used singly, reduce blood pressure and proteinuria, slow progression of kidney disease, and improve outcomes in patients who have heart failure, diabetes mellitus, or a history of myocardial infarction.^5–11 

While dual blockade with the combination of an ACE inhibitor and an ARB lowers blood pressure and proteinuria to a greater degree than monotherapy, dual blockade has been associated with higher rates of complications, including hyperkalemia.^12–17

RISK FACTORS FOR HYPERKALEMIA

ACE inhibitors and ARBs raise potassium, especially when used in combination. Other risk factors for hyperkalemia include the following—and note that some of them are also indications for ACE inhibitors and ARBs:

Renal insufficiency. The kidneys are responsible for over 90% of potassium removal in healthy individuals,^18,19 and the lower the GFR, the higher the risk of hyperkalemia.^3,20,21

Heart failure

Diabetes mellitus^6,21–23

Endogenous potassium load due to hemolysis, rhabdomyolysis, insulin deficiency, lactic acidosis, or gastrointestinal bleeding

Exogenous potassium load due to dietary consumption or blood products

Other medications, eg, sacubitril-valsartan, aldosterone antagonists, mineralocorticoid receptor antagonists, potassium-sparing diuretics, beta-adrenergic antagonists, nonsteroidal anti-inflammatory drugs, heparin, cyclosporine, trimethoprim, digoxin

Hypertension

Hypoaldosteronism (including type 4 renal tubular acidosis)

Addison disease

Advanced age

Lower body mass index.

Both hypokalemia and hyperkalemia are associated with a higher risk of death,^20,21,24  but in patients with heart failure, the survival benefit from ACE inhibitors, ARBs, and mineralocorticoid receptor antagonists outweighs the risk of hyperkalemia.^25–27 Weir and Rolfe²⁸ concluded that patients with heart failure and chronic kidney disease are at greatest risk of hyperkalemia from renin-angiotensin-aldosterone system inhibition, but the increases in potassium levels are small (about 0.1 to 0.3 mmol/L) and unlikely to be clinically significant.

Hyperkalemia tends to recur. Einhorn et al²⁰ found that nearly half of patients with chronic kidney disease who had an episode of hyperkalemia had 1 or more recurrent episodes within a year.

Another concern about using ACE inhibitors and ARBs, especially in patients with chronic kidney disease, is that the serum creatinine level tends to rise when starting these drugs,²⁹ although several studies have shown that an acute rise in creatinine may demonstrate that the drug is actually protecting the kidney.^30,31 Hirsch³² described this phenomenon as “prerenal success,” proposing that the decline in GFR is hemodynamic, secondary to a fall in intraglomerular pressure as a result of efferent vasodilation, and therefore should not be reversed.

Schmidt et al,^33,34 in a study in 122,363 patients who began ACE inhibitor or ARB therapy, found that cardiorenal outcomes were worse, with higher rates of end-stage renal disease, myocardial infarction, heart failure, and death, in those in whom creatinine rose by 30% or more since starting treatment. This trend was also seen, to a lesser degree, in those with a smaller increase in creatinine, suggesting that even this group of patients should receive close monitoring.

Whether renin-angiotensin-aldosterone system inhibitors provide a benefit in advanced progressive chronic kidney disease remains unclear.^35–37  The Angiotensin Converting Enzyme Inhibitor (ACEi)/Angiotensin Receptor Blocker (ARB) Withdrawal in Advanced Renal Disease trial (STOP-ACEi),³⁸ currently under way, will provide valuable data to help close this gap in our knowledge. This open-label randomized controlled trial is testing the hypothesis that stopping ACE inhibitor or ARB treatment, or a combination of both, compared with continuing these treatments, will improve or stabilize renal function in patients with progressive stage 4 or 5 chronic kidney disease.

NEED FOR MONITORING

Taken together, the above data suggest close and regular monitoring is required in patients receiving these drugs. However, monitoring tends to be lax.^34,37,39 A 2017 study of adherence to the guidelines for monitoring serum creatinine and potassium after starting an ACE inhibitor or ARB and subsequent discontinuation found that fewer than 10% of patients had follow-up within the recommended 2 weeks after starting these drugs.³⁴ Most patients with a creatinine rise of 30% or more or a potassium level higher than 6.0 mmol/L continued treatment. There was also no evidence of increased monitoring in those deemed at higher risk of these complications.

WHAT DO THE GUIDELINES SUGGEST?

ACE inhibitors and ARBs in chronic kidney disease and hypertension

Target blood pressures vary in guidelines from different organizations.^4,40–45 The 2017 joint guidelines of the American College of Cardiology and American Heart Association (ACC/AHA)⁴⁰ recommend a target blood pressure of 130/80 mm Hg or less in all patients irrespective of the level of proteinuria and whether they have diabetes mellitus, based on several studies.^46–48 In the elderly, other factors such as the risk of hypotension and falls must be taken into consideration in establishing the most appropriate blood pressure target.

In general, a renin-angiotensin-aldosterone system inhibitor is recommended if the patient has diabetes, stage 1, 2, or 3 chronic kidney disease, or proteinuria. For example, the guidelines recommend a renin-angiotensin-aldosterone system inhibitor in diabetic patients with albuminuria.

None of the guidelines recommend routine use of combination therapy.

ACE inhibitors and ARBs in heart failure

The 2017 ACC/AHA and Heart Failure Society of America (HFSA) guidelines for heart failure⁴⁹ recommend an ACE inhibitor or ARB for patients with stage C (symptomatic) heart failure with reduced ejection fraction, in view of the known cardiovascular morbidity and mortality benefits.

The European Society of Cardiology⁵⁰ recommends ACE inhibitors for patients with symptomatic heart failure with reduced ejection fraction, as well as those with asymptomatic left ventricular systolic dysfunction. In patients with stable coronary artery disease, an ACE inhibitor should be considered even with normal left ventricular function.

ARBs should be used as alternatives in those unable to tolerate ACE inhibitors.

Combination therapy should be avoided due to the increased risk of renal impairment and hyperkalemia but may be considered in patients with heart failure and reduced ejection fraction in whom other treatments are unsuitable. These include patients on beta-blockers who cannot tolerate mineralocorticoid receptor antagonists such as spironolactone. Combination therapy should be done only under strict supervision.⁵⁰

Close monitoring of serum potassium is recommended during ACE inhibitor or ARB use. Those at greatest risk of hyperkalemia include elderly patients, those taking other medications associated with hyperkalemia, and diabetic patients, because of their higher risk of renovascular disease.

Caution is advised when starting ACE inhibitor or ARB therapy in these high-risk groups as well as in patients with potassium levels higher than 5.0 mmol/L at baseline, at high risk of prerenal acute kidney injury, with known renal insufficiency, and with previous deterioration in renal function on these medications.^3,41,51

Before starting therapy, ensure that patients are volume-replete and measure baseline serum electrolytes and creatinine.^41,51

The ACC/AHA and HFSA recommend starting at a low dose and titrating upward slowly. If maximal doses are not tolerated, then a lower dose should be maintained.⁴⁹ The European Society of Cardiology guidelines⁵² suggest increasing the dose at no less than every 2 weeks unless in an inpatient setting. Blood testing should be done 7 to 14 days after starting therapy, after any titration in dosage, and every 4 months thereafter.⁵³

The guidelines generally agree that a rise in creatinine of up to 30% and a fall in eGFR of up to 25% is acceptable, with the need for regular monitoring, particularly in high-risk groups.^{40–42,51,52}

What if serum potassium or creatinine rises during treatment?

If hyperkalemia arises or renal function declines by a significant amount, one should first address contributing factors. If no improvement is seen, then the dose of the ACE inhibitor or ARB should be reduced by 50% and blood work repeated in 1 to 2 weeks. If the laboratory values do not return to an acceptable level, reducing the dose further or stopping the drug is advised.

Give dietary advice to all patients with chronic kidney disease being considered for a renin-angiotensin-aldosterone system inhibitor or for an increase in dose with a potassium level higher than 4.5 mmol/L. A low-potassium diet should aim for potassium intake of less than 50 or 75 mmol/day and sodium intake of less than 60 mmol/day for hypertensive patients with chronic kidney disease.

Review the patient’s medications if the baseline potassium level is higher than 5.0 mmol/L. Consider stopping potassium-sparing agents, digoxin, trimethoprim, and nonsteroidal anti-inflammatory drugs. Also think about starting a non–potassium-sparing diuretic as well as sodium bicarbonate to reduce potassium levels. Blood work should be repeated within 2 weeks after these changes.

Do not start a renin-angiotensin-aldosterone system inhibitor, or do not increase the dose, if the potassium level is elevated until measures have been taken to reduce the degree of hyperkalemia.⁵¹

In renal transplant recipients, renin-angiotensin-aldosterone system inhibitors are often preferred to manage hypertension in those who have proteinuria or cardiovascular disease. However, the risk of hyperkalemia is also greater with concomitant use of immunosuppressive drugs such as tacrolimus and cyclosporine. Management of complications should be approached according to guidelines discussed above.⁵¹

Monitor renal function, potassium. The National Institute for Health and Care Excellence guideline⁵⁴ advocates that baseline renal function testing should be followed by repeat blood testing 1 to 2 weeks after starting renin-angiotensin-aldosterone system inhibitors in patients with ischemic heart disease. The advice is similar when starting therapy in patients with chronic heart failure, emphasizing the need to monitor after each dose increment and to use clinical judgment when deciding to start treatment. The AHA advises caution in patients with renal insufficiency or a potassium level above 5.0 mmol/L.⁴⁹

Sick day rules. The National Institute for Health and Care Excellence encourages discussing “sick day rules” with patients starting renin-angiotensin-aldosterone system inhibitors. This means patients should be advised to temporarily stop taking nephrotoxic medications, including over-the-counter nonsteroidal anti-inflammatory drugs, in any potential state of illness or dehydration, such as diarrhea and vomiting. There is, however, little evidence that this advice can actually reduce the incidence of acute kidney injury.^55,56

OUR RECOMMENDATIONS

Our advice for managing patients receiving ACE inhibitors or ARBs is summarized in Table 1.

A highly active, water- and alcohol-soluble, basic pressor substance is formed when renin and renin-activator interact, for which we suggest the name “angiotonin.”

—Irvine H. Page and O.M. Helmer, 1940.¹

The renin-angiotensin-aldosterone system regulates salt and, in part, water homeostasis, and therefore blood pressure and fluid balance through its actions on the heart, kidneys, and blood vessels.² Drugs that target this system—angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs)—are used primarily to treat hypertension and also to treat chronic kidney disease and heart failure with reduced ejection fraction.

See related editorial

Controlling blood pressure is important, as hypertension increases the risk of myocardial infarction, cerebrovascular events, and progression of chronic kidney disease, which itself is a risk factor for cardiovascular disease. However, the benefit of these drugs is only partly due to their effect on blood pressure. They also reduce proteinuria, which is a graded risk factor for progression of kidney disease as well as morbidity and death from vascular events.³

Despite the benefits of ACE inhibitors and ARBs, concern about their adverse effects—especially hyperkalemia and a decline in renal function—has led to their underuse in patients likely to derive the greatest benefit.³

ACE INHIBITORS AND ARBs

ACE inhibitors, as their name indicates, inhibit conversion of angiotensin I to angiotensin II by ACE, resulting in vasodilation of the efferent arteriole and a drop in blood pressure. Inhibition of ACE, a kininase, also results in a rise in kinins. One of these, bradykinin, is associated with some of the side effects of this class of drugs such as cough, which affects 5% to 20% of patients.⁴ Elevation of bradykinin is also believed to account for ACE inhibitor-induced angioedema, an uncommon but potentially serious side effect. Kinins are also associated with desirable effects such as lowering blood pressure, increasing insulin sensitivity, and dilating blood vessels.

ARBs were developed as an alternative for patients unable to tolerate the adverse effects of ACE inhibitors. While ACE inhibitors reduce the activity of angiotensin II at both the AT1 and AT2 receptors, ARBs block only the AT1 receptors, thereby inhibiting their vasoconstricting activity on smooth muscle. ARBs also raise the levels of renin, angiotensin I, and angiotensin II as a result of feedback inhibition. Angiotensin II is associated with release of inflammatory mediators such as tumor necrosis factor alpha, cytokines, and chemokines, the consequences of which are also inhibited by ARBs, further preventing renal fibrosis and scarring from chronic inflammation.³

What is the evidence supporting the use of ACE inhibitors and ARBs?

ACE inhibitors and ARBs, used singly, reduce blood pressure and proteinuria, slow progression of kidney disease, and improve outcomes in patients who have heart failure, diabetes mellitus, or a history of myocardial infarction.^5–11 

While dual blockade with the combination of an ACE inhibitor and an ARB lowers blood pressure and proteinuria to a greater degree than monotherapy, dual blockade has been associated with higher rates of complications, including hyperkalemia.^12–17

RISK FACTORS FOR HYPERKALEMIA

ACE inhibitors and ARBs raise potassium, especially when used in combination. Other risk factors for hyperkalemia include the following—and note that some of them are also indications for ACE inhibitors and ARBs:

Renal insufficiency. The kidneys are responsible for over 90% of potassium removal in healthy individuals,^18,19 and the lower the GFR, the higher the risk of hyperkalemia.^3,20,21

Heart failure

Diabetes mellitus^6,21–23

Endogenous potassium load due to hemolysis, rhabdomyolysis, insulin deficiency, lactic acidosis, or gastrointestinal bleeding

Exogenous potassium load due to dietary consumption or blood products

Other medications, eg, sacubitril-valsartan, aldosterone antagonists, mineralocorticoid receptor antagonists, potassium-sparing diuretics, beta-adrenergic antagonists, nonsteroidal anti-inflammatory drugs, heparin, cyclosporine, trimethoprim, digoxin

Hypertension

Hypoaldosteronism (including type 4 renal tubular acidosis)

Addison disease

Advanced age

Lower body mass index.

Both hypokalemia and hyperkalemia are associated with a higher risk of death,^20,21,24  but in patients with heart failure, the survival benefit from ACE inhibitors, ARBs, and mineralocorticoid receptor antagonists outweighs the risk of hyperkalemia.^25–27 Weir and Rolfe²⁸ concluded that patients with heart failure and chronic kidney disease are at greatest risk of hyperkalemia from renin-angiotensin-aldosterone system inhibition, but the increases in potassium levels are small (about 0.1 to 0.3 mmol/L) and unlikely to be clinically significant.

Hyperkalemia tends to recur. Einhorn et al²⁰ found that nearly half of patients with chronic kidney disease who had an episode of hyperkalemia had 1 or more recurrent episodes within a year.

Another concern about using ACE inhibitors and ARBs, especially in patients with chronic kidney disease, is that the serum creatinine level tends to rise when starting these drugs,²⁹ although several studies have shown that an acute rise in creatinine may demonstrate that the drug is actually protecting the kidney.^30,31 Hirsch³² described this phenomenon as “prerenal success,” proposing that the decline in GFR is hemodynamic, secondary to a fall in intraglomerular pressure as a result of efferent vasodilation, and therefore should not be reversed.

Schmidt et al,^33,34 in a study in 122,363 patients who began ACE inhibitor or ARB therapy, found that cardiorenal outcomes were worse, with higher rates of end-stage renal disease, myocardial infarction, heart failure, and death, in those in whom creatinine rose by 30% or more since starting treatment. This trend was also seen, to a lesser degree, in those with a smaller increase in creatinine, suggesting that even this group of patients should receive close monitoring.

Whether renin-angiotensin-aldosterone system inhibitors provide a benefit in advanced progressive chronic kidney disease remains unclear.^35–37  The Angiotensin Converting Enzyme Inhibitor (ACEi)/Angiotensin Receptor Blocker (ARB) Withdrawal in Advanced Renal Disease trial (STOP-ACEi),³⁸ currently under way, will provide valuable data to help close this gap in our knowledge. This open-label randomized controlled trial is testing the hypothesis that stopping ACE inhibitor or ARB treatment, or a combination of both, compared with continuing these treatments, will improve or stabilize renal function in patients with progressive stage 4 or 5 chronic kidney disease.

NEED FOR MONITORING

Taken together, the above data suggest close and regular monitoring is required in patients receiving these drugs. However, monitoring tends to be lax.^34,37,39 A 2017 study of adherence to the guidelines for monitoring serum creatinine and potassium after starting an ACE inhibitor or ARB and subsequent discontinuation found that fewer than 10% of patients had follow-up within the recommended 2 weeks after starting these drugs.³⁴ Most patients with a creatinine rise of 30% or more or a potassium level higher than 6.0 mmol/L continued treatment. There was also no evidence of increased monitoring in those deemed at higher risk of these complications.

WHAT DO THE GUIDELINES SUGGEST?

ACE inhibitors and ARBs in chronic kidney disease and hypertension

Target blood pressures vary in guidelines from different organizations.^4,40–45 The 2017 joint guidelines of the American College of Cardiology and American Heart Association (ACC/AHA)⁴⁰ recommend a target blood pressure of 130/80 mm Hg or less in all patients irrespective of the level of proteinuria and whether they have diabetes mellitus, based on several studies.^46–48 In the elderly, other factors such as the risk of hypotension and falls must be taken into consideration in establishing the most appropriate blood pressure target.

In general, a renin-angiotensin-aldosterone system inhibitor is recommended if the patient has diabetes, stage 1, 2, or 3 chronic kidney disease, or proteinuria. For example, the guidelines recommend a renin-angiotensin-aldosterone system inhibitor in diabetic patients with albuminuria.

None of the guidelines recommend routine use of combination therapy.

ACE inhibitors and ARBs in heart failure

The 2017 ACC/AHA and Heart Failure Society of America (HFSA) guidelines for heart failure⁴⁹ recommend an ACE inhibitor or ARB for patients with stage C (symptomatic) heart failure with reduced ejection fraction, in view of the known cardiovascular morbidity and mortality benefits.

The European Society of Cardiology⁵⁰ recommends ACE inhibitors for patients with symptomatic heart failure with reduced ejection fraction, as well as those with asymptomatic left ventricular systolic dysfunction. In patients with stable coronary artery disease, an ACE inhibitor should be considered even with normal left ventricular function.

ARBs should be used as alternatives in those unable to tolerate ACE inhibitors.

Combination therapy should be avoided due to the increased risk of renal impairment and hyperkalemia but may be considered in patients with heart failure and reduced ejection fraction in whom other treatments are unsuitable. These include patients on beta-blockers who cannot tolerate mineralocorticoid receptor antagonists such as spironolactone. Combination therapy should be done only under strict supervision.⁵⁰

Close monitoring of serum potassium is recommended during ACE inhibitor or ARB use. Those at greatest risk of hyperkalemia include elderly patients, those taking other medications associated with hyperkalemia, and diabetic patients, because of their higher risk of renovascular disease.

Caution is advised when starting ACE inhibitor or ARB therapy in these high-risk groups as well as in patients with potassium levels higher than 5.0 mmol/L at baseline, at high risk of prerenal acute kidney injury, with known renal insufficiency, and with previous deterioration in renal function on these medications.^3,41,51

Before starting therapy, ensure that patients are volume-replete and measure baseline serum electrolytes and creatinine.^41,51

The ACC/AHA and HFSA recommend starting at a low dose and titrating upward slowly. If maximal doses are not tolerated, then a lower dose should be maintained.⁴⁹ The European Society of Cardiology guidelines⁵² suggest increasing the dose at no less than every 2 weeks unless in an inpatient setting. Blood testing should be done 7 to 14 days after starting therapy, after any titration in dosage, and every 4 months thereafter.⁵³

The guidelines generally agree that a rise in creatinine of up to 30% and a fall in eGFR of up to 25% is acceptable, with the need for regular monitoring, particularly in high-risk groups.^{40–42,51,52}

What if serum potassium or creatinine rises during treatment?

If hyperkalemia arises or renal function declines by a significant amount, one should first address contributing factors. If no improvement is seen, then the dose of the ACE inhibitor or ARB should be reduced by 50% and blood work repeated in 1 to 2 weeks. If the laboratory values do not return to an acceptable level, reducing the dose further or stopping the drug is advised.

Give dietary advice to all patients with chronic kidney disease being considered for a renin-angiotensin-aldosterone system inhibitor or for an increase in dose with a potassium level higher than 4.5 mmol/L. A low-potassium diet should aim for potassium intake of less than 50 or 75 mmol/day and sodium intake of less than 60 mmol/day for hypertensive patients with chronic kidney disease.

Review the patient’s medications if the baseline potassium level is higher than 5.0 mmol/L. Consider stopping potassium-sparing agents, digoxin, trimethoprim, and nonsteroidal anti-inflammatory drugs. Also think about starting a non–potassium-sparing diuretic as well as sodium bicarbonate to reduce potassium levels. Blood work should be repeated within 2 weeks after these changes.

Do not start a renin-angiotensin-aldosterone system inhibitor, or do not increase the dose, if the potassium level is elevated until measures have been taken to reduce the degree of hyperkalemia.⁵¹

In renal transplant recipients, renin-angiotensin-aldosterone system inhibitors are often preferred to manage hypertension in those who have proteinuria or cardiovascular disease. However, the risk of hyperkalemia is also greater with concomitant use of immunosuppressive drugs such as tacrolimus and cyclosporine. Management of complications should be approached according to guidelines discussed above.⁵¹

Monitor renal function, potassium. The National Institute for Health and Care Excellence guideline⁵⁴ advocates that baseline renal function testing should be followed by repeat blood testing 1 to 2 weeks after starting renin-angiotensin-aldosterone system inhibitors in patients with ischemic heart disease. The advice is similar when starting therapy in patients with chronic heart failure, emphasizing the need to monitor after each dose increment and to use clinical judgment when deciding to start treatment. The AHA advises caution in patients with renal insufficiency or a potassium level above 5.0 mmol/L.⁴⁹

Sick day rules. The National Institute for Health and Care Excellence encourages discussing “sick day rules” with patients starting renin-angiotensin-aldosterone system inhibitors. This means patients should be advised to temporarily stop taking nephrotoxic medications, including over-the-counter nonsteroidal anti-inflammatory drugs, in any potential state of illness or dehydration, such as diarrhea and vomiting. There is, however, little evidence that this advice can actually reduce the incidence of acute kidney injury.^55,56

OUR RECOMMENDATIONS

Our advice for managing patients receiving ACE inhibitors or ARBs is summarized in Table 1.

A highly active, water- and alcohol-soluble, basic pressor substance is formed when renin and renin-activator interact, for which we suggest the name “angiotonin.”

—Irvine H. Page and O.M. Helmer, 1940.¹

The renin-angiotensin-aldosterone system regulates salt and, in part, water homeostasis, and therefore blood pressure and fluid balance through its actions on the heart, kidneys, and blood vessels.² Drugs that target this system—angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs)—are used primarily to treat hypertension and also to treat chronic kidney disease and heart failure with reduced ejection fraction.

See related editorial

Controlling blood pressure is important, as hypertension increases the risk of myocardial infarction, cerebrovascular events, and progression of chronic kidney disease, which itself is a risk factor for cardiovascular disease. However, the benefit of these drugs is only partly due to their effect on blood pressure. They also reduce proteinuria, which is a graded risk factor for progression of kidney disease as well as morbidity and death from vascular events.³

Despite the benefits of ACE inhibitors and ARBs, concern about their adverse effects—especially hyperkalemia and a decline in renal function—has led to their underuse in patients likely to derive the greatest benefit.³

ACE INHIBITORS AND ARBs

ACE inhibitors, as their name indicates, inhibit conversion of angiotensin I to angiotensin II by ACE, resulting in vasodilation of the efferent arteriole and a drop in blood pressure. Inhibition of ACE, a kininase, also results in a rise in kinins. One of these, bradykinin, is associated with some of the side effects of this class of drugs such as cough, which affects 5% to 20% of patients.⁴ Elevation of bradykinin is also believed to account for ACE inhibitor-induced angioedema, an uncommon but potentially serious side effect. Kinins are also associated with desirable effects such as lowering blood pressure, increasing insulin sensitivity, and dilating blood vessels.

ARBs were developed as an alternative for patients unable to tolerate the adverse effects of ACE inhibitors. While ACE inhibitors reduce the activity of angiotensin II at both the AT1 and AT2 receptors, ARBs block only the AT1 receptors, thereby inhibiting their vasoconstricting activity on smooth muscle. ARBs also raise the levels of renin, angiotensin I, and angiotensin II as a result of feedback inhibition. Angiotensin II is associated with release of inflammatory mediators such as tumor necrosis factor alpha, cytokines, and chemokines, the consequences of which are also inhibited by ARBs, further preventing renal fibrosis and scarring from chronic inflammation.³

What is the evidence supporting the use of ACE inhibitors and ARBs?

ACE inhibitors and ARBs, used singly, reduce blood pressure and proteinuria, slow progression of kidney disease, and improve outcomes in patients who have heart failure, diabetes mellitus, or a history of myocardial infarction.^5–11 

While dual blockade with the combination of an ACE inhibitor and an ARB lowers blood pressure and proteinuria to a greater degree than monotherapy, dual blockade has been associated with higher rates of complications, including hyperkalemia.^12–17

RISK FACTORS FOR HYPERKALEMIA

ACE inhibitors and ARBs raise potassium, especially when used in combination. Other risk factors for hyperkalemia include the following—and note that some of them are also indications for ACE inhibitors and ARBs:

Renal insufficiency. The kidneys are responsible for over 90% of potassium removal in healthy individuals,^18,19 and the lower the GFR, the higher the risk of hyperkalemia.^3,20,21

Heart failure

Diabetes mellitus^6,21–23

Endogenous potassium load due to hemolysis, rhabdomyolysis, insulin deficiency, lactic acidosis, or gastrointestinal bleeding

Exogenous potassium load due to dietary consumption or blood products

Other medications, eg, sacubitril-valsartan, aldosterone antagonists, mineralocorticoid receptor antagonists, potassium-sparing diuretics, beta-adrenergic antagonists, nonsteroidal anti-inflammatory drugs, heparin, cyclosporine, trimethoprim, digoxin

Hypertension

Hypoaldosteronism (including type 4 renal tubular acidosis)

Addison disease

Advanced age

Lower body mass index.

Both hypokalemia and hyperkalemia are associated with a higher risk of death,^20,21,24  but in patients with heart failure, the survival benefit from ACE inhibitors, ARBs, and mineralocorticoid receptor antagonists outweighs the risk of hyperkalemia.^25–27 Weir and Rolfe²⁸ concluded that patients with heart failure and chronic kidney disease are at greatest risk of hyperkalemia from renin-angiotensin-aldosterone system inhibition, but the increases in potassium levels are small (about 0.1 to 0.3 mmol/L) and unlikely to be clinically significant.

Hyperkalemia tends to recur. Einhorn et al²⁰ found that nearly half of patients with chronic kidney disease who had an episode of hyperkalemia had 1 or more recurrent episodes within a year.

Another concern about using ACE inhibitors and ARBs, especially in patients with chronic kidney disease, is that the serum creatinine level tends to rise when starting these drugs,²⁹ although several studies have shown that an acute rise in creatinine may demonstrate that the drug is actually protecting the kidney.^30,31 Hirsch³² described this phenomenon as “prerenal success,” proposing that the decline in GFR is hemodynamic, secondary to a fall in intraglomerular pressure as a result of efferent vasodilation, and therefore should not be reversed.

Schmidt et al,^33,34 in a study in 122,363 patients who began ACE inhibitor or ARB therapy, found that cardiorenal outcomes were worse, with higher rates of end-stage renal disease, myocardial infarction, heart failure, and death, in those in whom creatinine rose by 30% or more since starting treatment. This trend was also seen, to a lesser degree, in those with a smaller increase in creatinine, suggesting that even this group of patients should receive close monitoring.

Whether renin-angiotensin-aldosterone system inhibitors provide a benefit in advanced progressive chronic kidney disease remains unclear.^35–37  The Angiotensin Converting Enzyme Inhibitor (ACEi)/Angiotensin Receptor Blocker (ARB) Withdrawal in Advanced Renal Disease trial (STOP-ACEi),³⁸ currently under way, will provide valuable data to help close this gap in our knowledge. This open-label randomized controlled trial is testing the hypothesis that stopping ACE inhibitor or ARB treatment, or a combination of both, compared with continuing these treatments, will improve or stabilize renal function in patients with progressive stage 4 or 5 chronic kidney disease.

NEED FOR MONITORING

Taken together, the above data suggest close and regular monitoring is required in patients receiving these drugs. However, monitoring tends to be lax.^34,37,39 A 2017 study of adherence to the guidelines for monitoring serum creatinine and potassium after starting an ACE inhibitor or ARB and subsequent discontinuation found that fewer than 10% of patients had follow-up within the recommended 2 weeks after starting these drugs.³⁴ Most patients with a creatinine rise of 30% or more or a potassium level higher than 6.0 mmol/L continued treatment. There was also no evidence of increased monitoring in those deemed at higher risk of these complications.

WHAT DO THE GUIDELINES SUGGEST?

ACE inhibitors and ARBs in chronic kidney disease and hypertension

Target blood pressures vary in guidelines from different organizations.^4,40–45 The 2017 joint guidelines of the American College of Cardiology and American Heart Association (ACC/AHA)⁴⁰ recommend a target blood pressure of 130/80 mm Hg or less in all patients irrespective of the level of proteinuria and whether they have diabetes mellitus, based on several studies.^46–48 In the elderly, other factors such as the risk of hypotension and falls must be taken into consideration in establishing the most appropriate blood pressure target.

In general, a renin-angiotensin-aldosterone system inhibitor is recommended if the patient has diabetes, stage 1, 2, or 3 chronic kidney disease, or proteinuria. For example, the guidelines recommend a renin-angiotensin-aldosterone system inhibitor in diabetic patients with albuminuria.

None of the guidelines recommend routine use of combination therapy.

ACE inhibitors and ARBs in heart failure

The 2017 ACC/AHA and Heart Failure Society of America (HFSA) guidelines for heart failure⁴⁹ recommend an ACE inhibitor or ARB for patients with stage C (symptomatic) heart failure with reduced ejection fraction, in view of the known cardiovascular morbidity and mortality benefits.

The European Society of Cardiology⁵⁰ recommends ACE inhibitors for patients with symptomatic heart failure with reduced ejection fraction, as well as those with asymptomatic left ventricular systolic dysfunction. In patients with stable coronary artery disease, an ACE inhibitor should be considered even with normal left ventricular function.

ARBs should be used as alternatives in those unable to tolerate ACE inhibitors.

Combination therapy should be avoided due to the increased risk of renal impairment and hyperkalemia but may be considered in patients with heart failure and reduced ejection fraction in whom other treatments are unsuitable. These include patients on beta-blockers who cannot tolerate mineralocorticoid receptor antagonists such as spironolactone. Combination therapy should be done only under strict supervision.⁵⁰

Close monitoring of serum potassium is recommended during ACE inhibitor or ARB use. Those at greatest risk of hyperkalemia include elderly patients, those taking other medications associated with hyperkalemia, and diabetic patients, because of their higher risk of renovascular disease.

Caution is advised when starting ACE inhibitor or ARB therapy in these high-risk groups as well as in patients with potassium levels higher than 5.0 mmol/L at baseline, at high risk of prerenal acute kidney injury, with known renal insufficiency, and with previous deterioration in renal function on these medications.^3,41,51

Before starting therapy, ensure that patients are volume-replete and measure baseline serum electrolytes and creatinine.^41,51

The ACC/AHA and HFSA recommend starting at a low dose and titrating upward slowly. If maximal doses are not tolerated, then a lower dose should be maintained.⁴⁹ The European Society of Cardiology guidelines⁵² suggest increasing the dose at no less than every 2 weeks unless in an inpatient setting. Blood testing should be done 7 to 14 days after starting therapy, after any titration in dosage, and every 4 months thereafter.⁵³

The guidelines generally agree that a rise in creatinine of up to 30% and a fall in eGFR of up to 25% is acceptable, with the need for regular monitoring, particularly in high-risk groups.^{40–42,51,52}

What if serum potassium or creatinine rises during treatment?

If hyperkalemia arises or renal function declines by a significant amount, one should first address contributing factors. If no improvement is seen, then the dose of the ACE inhibitor or ARB should be reduced by 50% and blood work repeated in 1 to 2 weeks. If the laboratory values do not return to an acceptable level, reducing the dose further or stopping the drug is advised.

Give dietary advice to all patients with chronic kidney disease being considered for a renin-angiotensin-aldosterone system inhibitor or for an increase in dose with a potassium level higher than 4.5 mmol/L. A low-potassium diet should aim for potassium intake of less than 50 or 75 mmol/day and sodium intake of less than 60 mmol/day for hypertensive patients with chronic kidney disease.

Review the patient’s medications if the baseline potassium level is higher than 5.0 mmol/L. Consider stopping potassium-sparing agents, digoxin, trimethoprim, and nonsteroidal anti-inflammatory drugs. Also think about starting a non–potassium-sparing diuretic as well as sodium bicarbonate to reduce potassium levels. Blood work should be repeated within 2 weeks after these changes.

Do not start a renin-angiotensin-aldosterone system inhibitor, or do not increase the dose, if the potassium level is elevated until measures have been taken to reduce the degree of hyperkalemia.⁵¹

In renal transplant recipients, renin-angiotensin-aldosterone system inhibitors are often preferred to manage hypertension in those who have proteinuria or cardiovascular disease. However, the risk of hyperkalemia is also greater with concomitant use of immunosuppressive drugs such as tacrolimus and cyclosporine. Management of complications should be approached according to guidelines discussed above.⁵¹

Monitor renal function, potassium. The National Institute for Health and Care Excellence guideline⁵⁴ advocates that baseline renal function testing should be followed by repeat blood testing 1 to 2 weeks after starting renin-angiotensin-aldosterone system inhibitors in patients with ischemic heart disease. The advice is similar when starting therapy in patients with chronic heart failure, emphasizing the need to monitor after each dose increment and to use clinical judgment when deciding to start treatment. The AHA advises caution in patients with renal insufficiency or a potassium level above 5.0 mmol/L.⁴⁹

Sick day rules. The National Institute for Health and Care Excellence encourages discussing “sick day rules” with patients starting renin-angiotensin-aldosterone system inhibitors. This means patients should be advised to temporarily stop taking nephrotoxic medications, including over-the-counter nonsteroidal anti-inflammatory drugs, in any potential state of illness or dehydration, such as diarrhea and vomiting. There is, however, little evidence that this advice can actually reduce the incidence of acute kidney injury.^55,56

OUR RECOMMENDATIONS

Our advice for managing patients receiving ACE inhibitors or ARBs is summarized in Table 1.

The Food and Drug Administration has given Fast Track designation to the development of dapagliflozin (Farxiga) to delay progression of renal failure and to prevent cardiovascular and renal death in patients with chronic kidney disease with and without type 2 diabetes, according to a release from AstraZeneca.

The Fast Track designation is meant to accelerate the development and review process for the treatment of serious conditions that have unmet therapeutic needs.

Dapagliflozin, an oral daily sodium-glucose transporter 2 inhibitor, is approved both as a monotherapy and a component of combination therapy for the improvement of glycemic control in patients with type 2 diabetes, according to the release. It is given as an adjunct to diet and exercise, and has also shown additional benefits of weight loss and reduction in blood pressure.

A phase 3, randomized, placebo-controlled trial, DAPA-CVD (NCT03036150), is currently underway to evaluate the drug’s efficacy specifically in terms of renal outcomes and cardiovascular mortality in patients with chronic kidney disease, with and without type 2 diabetes. Participants receive once-daily dapagliflozin or placebo in addition to standard care.

Taking dapagliflozin carries risks of hypotension, renal impairment, hypoglycemia, and other concerns. The most common adverse reactions (5% or greater incidence) include female genital mycotic infections, nasopharyngitis, and urinary tract infections. Full prescribing information can be found on the agency’s website.
 

[email protected]

The Food and Drug Administration has given Fast Track designation to the development of dapagliflozin (Farxiga) to delay progression of renal failure and to prevent cardiovascular and renal death in patients with chronic kidney disease with and without type 2 diabetes, according to a release from AstraZeneca.

The Fast Track designation is meant to accelerate the development and review process for the treatment of serious conditions that have unmet therapeutic needs.

Dapagliflozin, an oral daily sodium-glucose transporter 2 inhibitor, is approved both as a monotherapy and a component of combination therapy for the improvement of glycemic control in patients with type 2 diabetes, according to the release. It is given as an adjunct to diet and exercise, and has also shown additional benefits of weight loss and reduction in blood pressure.

A phase 3, randomized, placebo-controlled trial, DAPA-CVD (NCT03036150), is currently underway to evaluate the drug’s efficacy specifically in terms of renal outcomes and cardiovascular mortality in patients with chronic kidney disease, with and without type 2 diabetes. Participants receive once-daily dapagliflozin or placebo in addition to standard care.

Taking dapagliflozin carries risks of hypotension, renal impairment, hypoglycemia, and other concerns. The most common adverse reactions (5% or greater incidence) include female genital mycotic infections, nasopharyngitis, and urinary tract infections. Full prescribing information can be found on the agency’s website.
 

[email protected]

The Food and Drug Administration has given Fast Track designation to the development of dapagliflozin (Farxiga) to delay progression of renal failure and to prevent cardiovascular and renal death in patients with chronic kidney disease with and without type 2 diabetes, according to a release from AstraZeneca.

The Fast Track designation is meant to accelerate the development and review process for the treatment of serious conditions that have unmet therapeutic needs.

Dapagliflozin, an oral daily sodium-glucose transporter 2 inhibitor, is approved both as a monotherapy and a component of combination therapy for the improvement of glycemic control in patients with type 2 diabetes, according to the release. It is given as an adjunct to diet and exercise, and has also shown additional benefits of weight loss and reduction in blood pressure.

A phase 3, randomized, placebo-controlled trial, DAPA-CVD (NCT03036150), is currently underway to evaluate the drug’s efficacy specifically in terms of renal outcomes and cardiovascular mortality in patients with chronic kidney disease, with and without type 2 diabetes. Participants receive once-daily dapagliflozin or placebo in addition to standard care.

Taking dapagliflozin carries risks of hypotension, renal impairment, hypoglycemia, and other concerns. The most common adverse reactions (5% or greater incidence) include female genital mycotic infections, nasopharyngitis, and urinary tract infections. Full prescribing information can be found on the agency’s website.
 

[email protected]

Case

A 78-year-old woman with end-stage renal disease (ESRD) is hospitalized with cellulitis and is incidentally found to be in atrial fibrillation. She does not have a history of mitral stenosis, nor does she have a prosthetic valve. She does have a history of hypertension, diabetes, and prior stroke without residual deficits.

After counseling her about the risk of stroke associated with atrial fibrillation (AFib) she makes it clear she is interested in pharmacologic therapy to minimize her risk of stroke and asks what medication you would recommend for anticoagulation.

Brief overview of the issue

Anticoagulation for AFib is indicated for stroke prophylaxis in patients with an elevated risk of stroke. The CHA₂DS₂-VASc score is useful in calculating an individual patient’s risk of stroke and as a decision tool to determine who would benefit from anticoagulation, and it is recommended in the American Heart Association guidelines.¹

Low-risk patients (CHA₂DS₂-VASc score of 0 in men or 1 in women) should not be started on anticoagulation for stroke prophylaxis. For anyone with a risk factor, other than being female, anticoagulation is indicated and should be considered.

The guideline recommends anticoagulant therapy, not antiplatelet agents. For most of the recent past, this has meant a vitamin K antagonist (warfarin) or sometimes a low-molecular-weight heparin injected subcutaneously. Over the past decade, however, with the approval of multiple direct oral anticoagulants (DOACs), nonwarfarin oral anticoagulation has grown in popularity as the prophylactic medication of choice.²

While the data for patients with preserved renal function is robust, there is far less data to guide decision making for patients with end-stage renal disease.

Overview of the data

Until the introduction of DOACs, warfarin was the main agent used for stroke prophylaxis in patients with end-stage kidney disease and AFib. Professional guidelines favored warfarin for these patients who were mostly excluded from DOAC trials. Specialized conferences also looked at this issue.

The Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference, which reviewed chronic kidney disease and arrhythmias, noted that there were no randomized controlled trials that examined the efficacy and safety of anticoagulation in chronic kidney disease patients with estimated creatinine clearance less than 30 mL/min. They remarked that there was insufficient high-quality evidence to recommend warfarin for the prevention of stroke in patients with AFib and dialysis-dependent chronic kidney disease.

Since, according to other trials, DOACs had better safety profiles in other populations, the conference noted that lower-dose apixaban (2.5 mg orally twice daily) or rivaroxaban (15 mg daily) may be considered in this population until clinical safety data were available. Furthermore, the conference recommended that these patients be treated with a multidisciplinary approach in regards to anticoagulation and have an annual reevaluation of treatment goals, along with a risk-benefit assessment.³

Since the publication of the 2018 AHA guidelines and the guidance document that resulted from the KDIGO conference, additional research has been published comparing anticoagulation with a DOAC versus warfarin for AFib in patients with ESRD.

“Outcomes associated with apixaban use in patients with end-stage kidney disease and atrial fibrillation in the United States” was an observational, retrospective, cohort study that compared outcomes in dialysis patients who took warfarin for AFib with those who took apixaban.⁴ Patients’ data was taken from the U.S. Renal Data System database and were included in the final analysis if they had ESRD, a recent diagnosis of AFib or atrial flutter, and a new prescription for either warfarin or apixaban. Outcome measures were stroke or systemic embolism, major bleeding (critical site, transfusion, or death), gastrointestinal bleeding, intracranial bleeding, or death. Drug usage and compliance were assessed using Medicare Part D prescription information.

A total of 25,523 patients met the inclusion/exclusion criteria and had taken either warfarin (n = 23,172) or apixaban (n = 2,351). To account for selection bias in these cohorts, a subset of the warfarin patients was selected based on prognostic score matching. The prognostic score was calculated from the baseline characteristics (which included age, stroke history, diabetes, smoking, antiplatelet medication, liver disease, prior bleeding, and CHA₂DS₂-VASc score). Kaplan-Meier and Cox regression analysis were used to give hazard ratios and 95% confidence intervals for each outcome measure. Prespecified subgroup analyses were conducted to compare apixaban doses, where 44% were prescribed 5 mg b.i.d. and 56% were prescribed 2.5 mg b.i.d..

In the study, patients in the apixaban group had a significantly lower risk of major bleeding as compared with the warfarin group (HR, 0.72; 95% CI, 0.59-0.87; P less than .001) with overall high rates of major bleeding in both groups at 19.7 and 22.9 per 100 patient-years in the apixaban group and warfarin group, respectively. There was no difference in the rate of stroke/systemic embolism between patients receiving apixaban and warfarin (HR, 0.88; 95% CI, 0.69-1.12; P = .29). There was a nonsignificant trend toward decreased risk of GI bleeding in the apixaban group and no significant differences between the groups in the rates of intracranial bleeding. Apixaban was also associated with a nonsignificant trend toward lower risk of mortality (HR, 0.85; 95% CI, 0.71-1.01; P = .06).

Notably, censoring rates because of expired prescriptions or a 1-month gap between prescriptions were high in both groups and the majority of censoring occurred within the first 12 months. Additionally, in dose specific analyses, patients receiving the 5-mg, twice-daily dose were found to have statistically significant decreases in risk of stroke/systemic embolism (P = .035) and mortality (P = .005) as compared with the 2.5-mg, twice-daily dose without significant differences in GI or intracranial bleeding.

There are three ongoing, open-label, randomized, controlled trials examining anticoagulation for nonvalvular AFib in patients with ESRD on hemodialysis with two comparing apixaban to warfarin (or derivative) and the other warfarin versus no anticoagulation.⁵ All trials are in adult patients with documented AFib and CHA₂DS₂-VASc score of at least 2. AKADIA (Germany based) plans to enroll 222 patients and compares a vitamin K antagonist (INR goal, 2-3) with 2.5-mg b.i.d. apixaban patients with ESRD on hemodialysis for at least 3 months with primary outcome of major and clinically relevant nonmajor bleeding and secondary outcome of thromboembolic events, as well as apixaban levels pre- and post hemodialysis.

RENAL-AF (U.S. based) plans to enrolled 762 patients and compares 5-mg b.i.d. apixaban (with 2.5 mg for selected patients) with warfarin in people of chronic hemodialysis with primary outcome of days to first major or clinically relevant nonmajor bleeding event and secondary outcome of stroke, systemic embolism, mortality, adherence and plasma apixaban levels. AVKDIAL (France based) plans to enroll 855 patients and compares no anticoagulation with vitamin K antagonists in patients on hemodialysis for at least 1 month, with primary outcome of cumulative incidence of severe bleeding and thrombosis.

Application of the data to our original case

Our patient is Medicare age with ESRD and newly diagnosed nonvalvular AFib. Recent data suggests apixaban could be used for stroke prevention instead of the prior standard of care, warfarin. This approach is supported in the 2019 guidelines.¹

Patients with ESRD have an increased risk of bleeding and apixaban was shown to have less bleeding complications than warfarin in this analysis. However, only standard-dose apixaban was associated with a statistically significant lower risk of stroke/systemic embolism, major bleeding, and death. Reduced-dose apixaban had a lower risk of major bleeding but no difference for stroke/systemic embolism or death. Reduced-dose apixaban is used for patients who have two out of the following three criteria: aged at least 80 years, weight of at least 60 kg, and creatinine of at least 1.5 mg/dL. Therefore, many Medicare-age patients with ESRD would not be indicated for the dose of apixaban that was shown to improve the most important outcomes of stroke/SE and death.

It may still be beneficial to use apixaban in this patient since it appears to work as well as warfarin for stroke/systemic embolism prevention with less bleeding complications.

Bottom line

For patients who have decided to pursue an anticoagulation strategy for stroke prevention in AFib and have end-stage renal disease, either warfarin or apixaban are sensible options.

Dr. Farber is a medical instructor at Duke University Health System in Durham, N.C. Dr. Stafford is a medical instructor at Duke University. Dr. Sata is assistant professor of medicine at Duke University. Dr. Abdo and Dr. Menon are hospitalists at Duke University. Dr. Brooks is assistant professor of medicine at Duke University. Dr. Wachter is associate medical director at Duke Regional Hospital and assistant professor of medicine at Duke University. Dr. Sharma is associate medical director for clinical education in hospital medicine at Duke Regional Hospital and assistant professor of medicine at Duke University.

References

1. January CT et al. 2019 AHA/ACC/HRS focused update of the 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Circulation. 2019;139. doi: 1161/CIR.0000000000000665.

2. Lippi G et al. Direct oral anticoagulants: Analysis of worldwide use and popularity using Google Trends. Ann Transl Med. 2017 Aug; 5(16):322. doi: 10.21037/atm.2017.06.65.

3. Turakhia MP et al. Chronic kidney disease and arrhythmias: Conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference. Eur Heart J. 2018 Jun 21;39(24):2314-25. doi: 10.1093/eurheartj/ehy060.

4. Siontis KC et al. Outcomes associated with apixaban use in patients with end-stage kidney disease and atrial fibrillation in the United States. Circulation. 2018 Oct 9;138(15):1519-29. doi: 10.1161/CIRCULATIONAHA.118.035418.

5. Nigwekar SU et al. Long-term anticoagulation for patient receiving dialysis: Tilting the benefit-to-risk ratio? Circulation. 2018 Oct 9;138(15):1530-3. doi: 10.1161/CIRCULATIONAHA.118.037091.

Key points

• According to 2019 American Heart Association guidelines, warfarin or apixaban are reasonable options for stroke prevention for patients who have end-stage renal disease and who plan for anticoagulation because of atrial fibrillation.
• Recent observational data suggests that apixaban may be safer than warfarin in this population.
• Several randomized, controlled trials are ongoing that may help determine the optimal agent to use in this setting.
• Until more definitive data is available, a reasonable approach is to discuss the risks and benefits of various treatment strategies with patients, and engage a multidisciplinary team (cardiologist, nephrologist, primary care provider, pharmacist) in the decision making process.

Additional reading

January CT et al. 2019 AHA/ACC/HRS focused update of the 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Circulation. 2019;139. doi: 1161/CIR.0000000000000665.

Nigwekar SU et al. Long-term anticoagulation for patient receiving dialysis: Tilting the benefit to risk ratio? Circulation. 2018 Oct 9;138(15):1530-3. doi: 10.1161/CIRCULATIONAHA.118.037091.

Garlo KG et al. Demystifying the benefits and harms of anticoagulation for atrial fibrillation in chronic kidney disease. Clin J Am Soc Nephrol 2019;14:125-36. doi: 10.2215/CJN.06430518.

Quiz

Two days ago you admitted a 72-year-old woman with end-stage renal disease on dialysis who had developed new-onset atrial fibrillation causing a mild acute diastolic congestive heart failure exacerbation. Transthoracic ECG showed a preserved left ventricular ejection fraction and no significant valvular disease. After two sessions of dialysis in the hospital and initiation of a beta-blocker for control of her heart rate, she is stable and ready for discharge. Her discharge weight is 75 kg.

Which of the following recommendations should you make to this patient regarding anticoagulation for prevention of stroke and systemic embolism from atrial fibrillation?

A. Take warfarin with a international normalized ratio goal of 2.5.

B. Take apixaban 2.5 mg twice a day.

C. Take apixaban 5 mg twice a day.

D. Discuss the risks/benefits of various treatment approaches with the patient, and involve the hospital pharmacist as well as the patient’s nephrologist, cardiologist, and/or primary care provider in the decision making process to reach a consensus and to ensure a safe follow-up plan.

The best answer is D. While A, B, and C are all reasonable approaches based on the available data and current guidelines, the best approach is to involve the patient and the multidisciplinary team in the decision making process. When more clinical trial data becomes available in the future, the optimal approach to managing patients such as this one may become clearer, but until then it makes sense to take into account individual patient characteristics and patient preferences.

Case

A 78-year-old woman with end-stage renal disease (ESRD) is hospitalized with cellulitis and is incidentally found to be in atrial fibrillation. She does not have a history of mitral stenosis, nor does she have a prosthetic valve. She does have a history of hypertension, diabetes, and prior stroke without residual deficits.

After counseling her about the risk of stroke associated with atrial fibrillation (AFib) she makes it clear she is interested in pharmacologic therapy to minimize her risk of stroke and asks what medication you would recommend for anticoagulation.

Brief overview of the issue

Anticoagulation for AFib is indicated for stroke prophylaxis in patients with an elevated risk of stroke. The CHA₂DS₂-VASc score is useful in calculating an individual patient’s risk of stroke and as a decision tool to determine who would benefit from anticoagulation, and it is recommended in the American Heart Association guidelines.¹

Low-risk patients (CHA₂DS₂-VASc score of 0 in men or 1 in women) should not be started on anticoagulation for stroke prophylaxis. For anyone with a risk factor, other than being female, anticoagulation is indicated and should be considered.

The guideline recommends anticoagulant therapy, not antiplatelet agents. For most of the recent past, this has meant a vitamin K antagonist (warfarin) or sometimes a low-molecular-weight heparin injected subcutaneously. Over the past decade, however, with the approval of multiple direct oral anticoagulants (DOACs), nonwarfarin oral anticoagulation has grown in popularity as the prophylactic medication of choice.²

While the data for patients with preserved renal function is robust, there is far less data to guide decision making for patients with end-stage renal disease.

Overview of the data

Until the introduction of DOACs, warfarin was the main agent used for stroke prophylaxis in patients with end-stage kidney disease and AFib. Professional guidelines favored warfarin for these patients who were mostly excluded from DOAC trials. Specialized conferences also looked at this issue.

The Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference, which reviewed chronic kidney disease and arrhythmias, noted that there were no randomized controlled trials that examined the efficacy and safety of anticoagulation in chronic kidney disease patients with estimated creatinine clearance less than 30 mL/min. They remarked that there was insufficient high-quality evidence to recommend warfarin for the prevention of stroke in patients with AFib and dialysis-dependent chronic kidney disease.

Since, according to other trials, DOACs had better safety profiles in other populations, the conference noted that lower-dose apixaban (2.5 mg orally twice daily) or rivaroxaban (15 mg daily) may be considered in this population until clinical safety data were available. Furthermore, the conference recommended that these patients be treated with a multidisciplinary approach in regards to anticoagulation and have an annual reevaluation of treatment goals, along with a risk-benefit assessment.³

Since the publication of the 2018 AHA guidelines and the guidance document that resulted from the KDIGO conference, additional research has been published comparing anticoagulation with a DOAC versus warfarin for AFib in patients with ESRD.

“Outcomes associated with apixaban use in patients with end-stage kidney disease and atrial fibrillation in the United States” was an observational, retrospective, cohort study that compared outcomes in dialysis patients who took warfarin for AFib with those who took apixaban.⁴ Patients’ data was taken from the U.S. Renal Data System database and were included in the final analysis if they had ESRD, a recent diagnosis of AFib or atrial flutter, and a new prescription for either warfarin or apixaban. Outcome measures were stroke or systemic embolism, major bleeding (critical site, transfusion, or death), gastrointestinal bleeding, intracranial bleeding, or death. Drug usage and compliance were assessed using Medicare Part D prescription information.

A total of 25,523 patients met the inclusion/exclusion criteria and had taken either warfarin (n = 23,172) or apixaban (n = 2,351). To account for selection bias in these cohorts, a subset of the warfarin patients was selected based on prognostic score matching. The prognostic score was calculated from the baseline characteristics (which included age, stroke history, diabetes, smoking, antiplatelet medication, liver disease, prior bleeding, and CHA₂DS₂-VASc score). Kaplan-Meier and Cox regression analysis were used to give hazard ratios and 95% confidence intervals for each outcome measure. Prespecified subgroup analyses were conducted to compare apixaban doses, where 44% were prescribed 5 mg b.i.d. and 56% were prescribed 2.5 mg b.i.d..

In the study, patients in the apixaban group had a significantly lower risk of major bleeding as compared with the warfarin group (HR, 0.72; 95% CI, 0.59-0.87; P less than .001) with overall high rates of major bleeding in both groups at 19.7 and 22.9 per 100 patient-years in the apixaban group and warfarin group, respectively. There was no difference in the rate of stroke/systemic embolism between patients receiving apixaban and warfarin (HR, 0.88; 95% CI, 0.69-1.12; P = .29). There was a nonsignificant trend toward decreased risk of GI bleeding in the apixaban group and no significant differences between the groups in the rates of intracranial bleeding. Apixaban was also associated with a nonsignificant trend toward lower risk of mortality (HR, 0.85; 95% CI, 0.71-1.01; P = .06).

Notably, censoring rates because of expired prescriptions or a 1-month gap between prescriptions were high in both groups and the majority of censoring occurred within the first 12 months. Additionally, in dose specific analyses, patients receiving the 5-mg, twice-daily dose were found to have statistically significant decreases in risk of stroke/systemic embolism (P = .035) and mortality (P = .005) as compared with the 2.5-mg, twice-daily dose without significant differences in GI or intracranial bleeding.

There are three ongoing, open-label, randomized, controlled trials examining anticoagulation for nonvalvular AFib in patients with ESRD on hemodialysis with two comparing apixaban to warfarin (or derivative) and the other warfarin versus no anticoagulation.⁵ All trials are in adult patients with documented AFib and CHA₂DS₂-VASc score of at least 2. AKADIA (Germany based) plans to enroll 222 patients and compares a vitamin K antagonist (INR goal, 2-3) with 2.5-mg b.i.d. apixaban patients with ESRD on hemodialysis for at least 3 months with primary outcome of major and clinically relevant nonmajor bleeding and secondary outcome of thromboembolic events, as well as apixaban levels pre- and post hemodialysis.

RENAL-AF (U.S. based) plans to enrolled 762 patients and compares 5-mg b.i.d. apixaban (with 2.5 mg for selected patients) with warfarin in people of chronic hemodialysis with primary outcome of days to first major or clinically relevant nonmajor bleeding event and secondary outcome of stroke, systemic embolism, mortality, adherence and plasma apixaban levels. AVKDIAL (France based) plans to enroll 855 patients and compares no anticoagulation with vitamin K antagonists in patients on hemodialysis for at least 1 month, with primary outcome of cumulative incidence of severe bleeding and thrombosis.

Application of the data to our original case

Our patient is Medicare age with ESRD and newly diagnosed nonvalvular AFib. Recent data suggests apixaban could be used for stroke prevention instead of the prior standard of care, warfarin. This approach is supported in the 2019 guidelines.¹

Patients with ESRD have an increased risk of bleeding and apixaban was shown to have less bleeding complications than warfarin in this analysis. However, only standard-dose apixaban was associated with a statistically significant lower risk of stroke/systemic embolism, major bleeding, and death. Reduced-dose apixaban had a lower risk of major bleeding but no difference for stroke/systemic embolism or death. Reduced-dose apixaban is used for patients who have two out of the following three criteria: aged at least 80 years, weight of at least 60 kg, and creatinine of at least 1.5 mg/dL. Therefore, many Medicare-age patients with ESRD would not be indicated for the dose of apixaban that was shown to improve the most important outcomes of stroke/SE and death.

It may still be beneficial to use apixaban in this patient since it appears to work as well as warfarin for stroke/systemic embolism prevention with less bleeding complications.

Bottom line

For patients who have decided to pursue an anticoagulation strategy for stroke prevention in AFib and have end-stage renal disease, either warfarin or apixaban are sensible options.

Dr. Farber is a medical instructor at Duke University Health System in Durham, N.C. Dr. Stafford is a medical instructor at Duke University. Dr. Sata is assistant professor of medicine at Duke University. Dr. Abdo and Dr. Menon are hospitalists at Duke University. Dr. Brooks is assistant professor of medicine at Duke University. Dr. Wachter is associate medical director at Duke Regional Hospital and assistant professor of medicine at Duke University. Dr. Sharma is associate medical director for clinical education in hospital medicine at Duke Regional Hospital and assistant professor of medicine at Duke University.

References

1. January CT et al. 2019 AHA/ACC/HRS focused update of the 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Circulation. 2019;139. doi: 1161/CIR.0000000000000665.

2. Lippi G et al. Direct oral anticoagulants: Analysis of worldwide use and popularity using Google Trends. Ann Transl Med. 2017 Aug; 5(16):322. doi: 10.21037/atm.2017.06.65.

3. Turakhia MP et al. Chronic kidney disease and arrhythmias: Conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference. Eur Heart J. 2018 Jun 21;39(24):2314-25. doi: 10.1093/eurheartj/ehy060.

4. Siontis KC et al. Outcomes associated with apixaban use in patients with end-stage kidney disease and atrial fibrillation in the United States. Circulation. 2018 Oct 9;138(15):1519-29. doi: 10.1161/CIRCULATIONAHA.118.035418.

5. Nigwekar SU et al. Long-term anticoagulation for patient receiving dialysis: Tilting the benefit-to-risk ratio? Circulation. 2018 Oct 9;138(15):1530-3. doi: 10.1161/CIRCULATIONAHA.118.037091.

Key points

• According to 2019 American Heart Association guidelines, warfarin or apixaban are reasonable options for stroke prevention for patients who have end-stage renal disease and who plan for anticoagulation because of atrial fibrillation.
• Recent observational data suggests that apixaban may be safer than warfarin in this population.
• Several randomized, controlled trials are ongoing that may help determine the optimal agent to use in this setting.
• Until more definitive data is available, a reasonable approach is to discuss the risks and benefits of various treatment strategies with patients, and engage a multidisciplinary team (cardiologist, nephrologist, primary care provider, pharmacist) in the decision making process.

Additional reading

January CT et al. 2019 AHA/ACC/HRS focused update of the 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Circulation. 2019;139. doi: 1161/CIR.0000000000000665.

Nigwekar SU et al. Long-term anticoagulation for patient receiving dialysis: Tilting the benefit to risk ratio? Circulation. 2018 Oct 9;138(15):1530-3. doi: 10.1161/CIRCULATIONAHA.118.037091.

Garlo KG et al. Demystifying the benefits and harms of anticoagulation for atrial fibrillation in chronic kidney disease. Clin J Am Soc Nephrol 2019;14:125-36. doi: 10.2215/CJN.06430518.

Quiz

Two days ago you admitted a 72-year-old woman with end-stage renal disease on dialysis who had developed new-onset atrial fibrillation causing a mild acute diastolic congestive heart failure exacerbation. Transthoracic ECG showed a preserved left ventricular ejection fraction and no significant valvular disease. After two sessions of dialysis in the hospital and initiation of a beta-blocker for control of her heart rate, she is stable and ready for discharge. Her discharge weight is 75 kg.

Which of the following recommendations should you make to this patient regarding anticoagulation for prevention of stroke and systemic embolism from atrial fibrillation?

A. Take warfarin with a international normalized ratio goal of 2.5.

B. Take apixaban 2.5 mg twice a day.

C. Take apixaban 5 mg twice a day.

D. Discuss the risks/benefits of various treatment approaches with the patient, and involve the hospital pharmacist as well as the patient’s nephrologist, cardiologist, and/or primary care provider in the decision making process to reach a consensus and to ensure a safe follow-up plan.

The best answer is D. While A, B, and C are all reasonable approaches based on the available data and current guidelines, the best approach is to involve the patient and the multidisciplinary team in the decision making process. When more clinical trial data becomes available in the future, the optimal approach to managing patients such as this one may become clearer, but until then it makes sense to take into account individual patient characteristics and patient preferences.

Case

A 78-year-old woman with end-stage renal disease (ESRD) is hospitalized with cellulitis and is incidentally found to be in atrial fibrillation. She does not have a history of mitral stenosis, nor does she have a prosthetic valve. She does have a history of hypertension, diabetes, and prior stroke without residual deficits.

After counseling her about the risk of stroke associated with atrial fibrillation (AFib) she makes it clear she is interested in pharmacologic therapy to minimize her risk of stroke and asks what medication you would recommend for anticoagulation.

Brief overview of the issue

Anticoagulation for AFib is indicated for stroke prophylaxis in patients with an elevated risk of stroke. The CHA₂DS₂-VASc score is useful in calculating an individual patient’s risk of stroke and as a decision tool to determine who would benefit from anticoagulation, and it is recommended in the American Heart Association guidelines.¹

Low-risk patients (CHA₂DS₂-VASc score of 0 in men or 1 in women) should not be started on anticoagulation for stroke prophylaxis. For anyone with a risk factor, other than being female, anticoagulation is indicated and should be considered.

The guideline recommends anticoagulant therapy, not antiplatelet agents. For most of the recent past, this has meant a vitamin K antagonist (warfarin) or sometimes a low-molecular-weight heparin injected subcutaneously. Over the past decade, however, with the approval of multiple direct oral anticoagulants (DOACs), nonwarfarin oral anticoagulation has grown in popularity as the prophylactic medication of choice.²

While the data for patients with preserved renal function is robust, there is far less data to guide decision making for patients with end-stage renal disease.

Overview of the data

Until the introduction of DOACs, warfarin was the main agent used for stroke prophylaxis in patients with end-stage kidney disease and AFib. Professional guidelines favored warfarin for these patients who were mostly excluded from DOAC trials. Specialized conferences also looked at this issue.

The Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference, which reviewed chronic kidney disease and arrhythmias, noted that there were no randomized controlled trials that examined the efficacy and safety of anticoagulation in chronic kidney disease patients with estimated creatinine clearance less than 30 mL/min. They remarked that there was insufficient high-quality evidence to recommend warfarin for the prevention of stroke in patients with AFib and dialysis-dependent chronic kidney disease.

Since, according to other trials, DOACs had better safety profiles in other populations, the conference noted that lower-dose apixaban (2.5 mg orally twice daily) or rivaroxaban (15 mg daily) may be considered in this population until clinical safety data were available. Furthermore, the conference recommended that these patients be treated with a multidisciplinary approach in regards to anticoagulation and have an annual reevaluation of treatment goals, along with a risk-benefit assessment.³

Since the publication of the 2018 AHA guidelines and the guidance document that resulted from the KDIGO conference, additional research has been published comparing anticoagulation with a DOAC versus warfarin for AFib in patients with ESRD.

“Outcomes associated with apixaban use in patients with end-stage kidney disease and atrial fibrillation in the United States” was an observational, retrospective, cohort study that compared outcomes in dialysis patients who took warfarin for AFib with those who took apixaban.⁴ Patients’ data was taken from the U.S. Renal Data System database and were included in the final analysis if they had ESRD, a recent diagnosis of AFib or atrial flutter, and a new prescription for either warfarin or apixaban. Outcome measures were stroke or systemic embolism, major bleeding (critical site, transfusion, or death), gastrointestinal bleeding, intracranial bleeding, or death. Drug usage and compliance were assessed using Medicare Part D prescription information.

A total of 25,523 patients met the inclusion/exclusion criteria and had taken either warfarin (n = 23,172) or apixaban (n = 2,351). To account for selection bias in these cohorts, a subset of the warfarin patients was selected based on prognostic score matching. The prognostic score was calculated from the baseline characteristics (which included age, stroke history, diabetes, smoking, antiplatelet medication, liver disease, prior bleeding, and CHA₂DS₂-VASc score). Kaplan-Meier and Cox regression analysis were used to give hazard ratios and 95% confidence intervals for each outcome measure. Prespecified subgroup analyses were conducted to compare apixaban doses, where 44% were prescribed 5 mg b.i.d. and 56% were prescribed 2.5 mg b.i.d..

In the study, patients in the apixaban group had a significantly lower risk of major bleeding as compared with the warfarin group (HR, 0.72; 95% CI, 0.59-0.87; P less than .001) with overall high rates of major bleeding in both groups at 19.7 and 22.9 per 100 patient-years in the apixaban group and warfarin group, respectively. There was no difference in the rate of stroke/systemic embolism between patients receiving apixaban and warfarin (HR, 0.88; 95% CI, 0.69-1.12; P = .29). There was a nonsignificant trend toward decreased risk of GI bleeding in the apixaban group and no significant differences between the groups in the rates of intracranial bleeding. Apixaban was also associated with a nonsignificant trend toward lower risk of mortality (HR, 0.85; 95% CI, 0.71-1.01; P = .06).

Notably, censoring rates because of expired prescriptions or a 1-month gap between prescriptions were high in both groups and the majority of censoring occurred within the first 12 months. Additionally, in dose specific analyses, patients receiving the 5-mg, twice-daily dose were found to have statistically significant decreases in risk of stroke/systemic embolism (P = .035) and mortality (P = .005) as compared with the 2.5-mg, twice-daily dose without significant differences in GI or intracranial bleeding.

There are three ongoing, open-label, randomized, controlled trials examining anticoagulation for nonvalvular AFib in patients with ESRD on hemodialysis with two comparing apixaban to warfarin (or derivative) and the other warfarin versus no anticoagulation.⁵ All trials are in adult patients with documented AFib and CHA₂DS₂-VASc score of at least 2. AKADIA (Germany based) plans to enroll 222 patients and compares a vitamin K antagonist (INR goal, 2-3) with 2.5-mg b.i.d. apixaban patients with ESRD on hemodialysis for at least 3 months with primary outcome of major and clinically relevant nonmajor bleeding and secondary outcome of thromboembolic events, as well as apixaban levels pre- and post hemodialysis.

RENAL-AF (U.S. based) plans to enrolled 762 patients and compares 5-mg b.i.d. apixaban (with 2.5 mg for selected patients) with warfarin in people of chronic hemodialysis with primary outcome of days to first major or clinically relevant nonmajor bleeding event and secondary outcome of stroke, systemic embolism, mortality, adherence and plasma apixaban levels. AVKDIAL (France based) plans to enroll 855 patients and compares no anticoagulation with vitamin K antagonists in patients on hemodialysis for at least 1 month, with primary outcome of cumulative incidence of severe bleeding and thrombosis.

Application of the data to our original case

Our patient is Medicare age with ESRD and newly diagnosed nonvalvular AFib. Recent data suggests apixaban could be used for stroke prevention instead of the prior standard of care, warfarin. This approach is supported in the 2019 guidelines.¹

Patients with ESRD have an increased risk of bleeding and apixaban was shown to have less bleeding complications than warfarin in this analysis. However, only standard-dose apixaban was associated with a statistically significant lower risk of stroke/systemic embolism, major bleeding, and death. Reduced-dose apixaban had a lower risk of major bleeding but no difference for stroke/systemic embolism or death. Reduced-dose apixaban is used for patients who have two out of the following three criteria: aged at least 80 years, weight of at least 60 kg, and creatinine of at least 1.5 mg/dL. Therefore, many Medicare-age patients with ESRD would not be indicated for the dose of apixaban that was shown to improve the most important outcomes of stroke/SE and death.

It may still be beneficial to use apixaban in this patient since it appears to work as well as warfarin for stroke/systemic embolism prevention with less bleeding complications.

Bottom line

For patients who have decided to pursue an anticoagulation strategy for stroke prevention in AFib and have end-stage renal disease, either warfarin or apixaban are sensible options.

Dr. Farber is a medical instructor at Duke University Health System in Durham, N.C. Dr. Stafford is a medical instructor at Duke University. Dr. Sata is assistant professor of medicine at Duke University. Dr. Abdo and Dr. Menon are hospitalists at Duke University. Dr. Brooks is assistant professor of medicine at Duke University. Dr. Wachter is associate medical director at Duke Regional Hospital and assistant professor of medicine at Duke University. Dr. Sharma is associate medical director for clinical education in hospital medicine at Duke Regional Hospital and assistant professor of medicine at Duke University.

References

1. January CT et al. 2019 AHA/ACC/HRS focused update of the 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Circulation. 2019;139. doi: 1161/CIR.0000000000000665.

2. Lippi G et al. Direct oral anticoagulants: Analysis of worldwide use and popularity using Google Trends. Ann Transl Med. 2017 Aug; 5(16):322. doi: 10.21037/atm.2017.06.65.

3. Turakhia MP et al. Chronic kidney disease and arrhythmias: Conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference. Eur Heart J. 2018 Jun 21;39(24):2314-25. doi: 10.1093/eurheartj/ehy060.

4. Siontis KC et al. Outcomes associated with apixaban use in patients with end-stage kidney disease and atrial fibrillation in the United States. Circulation. 2018 Oct 9;138(15):1519-29. doi: 10.1161/CIRCULATIONAHA.118.035418.

5. Nigwekar SU et al. Long-term anticoagulation for patient receiving dialysis: Tilting the benefit-to-risk ratio? Circulation. 2018 Oct 9;138(15):1530-3. doi: 10.1161/CIRCULATIONAHA.118.037091.

Key points

• According to 2019 American Heart Association guidelines, warfarin or apixaban are reasonable options for stroke prevention for patients who have end-stage renal disease and who plan for anticoagulation because of atrial fibrillation.
• Recent observational data suggests that apixaban may be safer than warfarin in this population.
• Several randomized, controlled trials are ongoing that may help determine the optimal agent to use in this setting.
• Until more definitive data is available, a reasonable approach is to discuss the risks and benefits of various treatment strategies with patients, and engage a multidisciplinary team (cardiologist, nephrologist, primary care provider, pharmacist) in the decision making process.

Additional reading

January CT et al. 2019 AHA/ACC/HRS focused update of the 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Circulation. 2019;139. doi: 1161/CIR.0000000000000665.

Nigwekar SU et al. Long-term anticoagulation for patient receiving dialysis: Tilting the benefit to risk ratio? Circulation. 2018 Oct 9;138(15):1530-3. doi: 10.1161/CIRCULATIONAHA.118.037091.

Garlo KG et al. Demystifying the benefits and harms of anticoagulation for atrial fibrillation in chronic kidney disease. Clin J Am Soc Nephrol 2019;14:125-36. doi: 10.2215/CJN.06430518.

Quiz

Two days ago you admitted a 72-year-old woman with end-stage renal disease on dialysis who had developed new-onset atrial fibrillation causing a mild acute diastolic congestive heart failure exacerbation. Transthoracic ECG showed a preserved left ventricular ejection fraction and no significant valvular disease. After two sessions of dialysis in the hospital and initiation of a beta-blocker for control of her heart rate, she is stable and ready for discharge. Her discharge weight is 75 kg.

Which of the following recommendations should you make to this patient regarding anticoagulation for prevention of stroke and systemic embolism from atrial fibrillation?

A. Take warfarin with a international normalized ratio goal of 2.5.

B. Take apixaban 2.5 mg twice a day.

C. Take apixaban 5 mg twice a day.

D. Discuss the risks/benefits of various treatment approaches with the patient, and involve the hospital pharmacist as well as the patient’s nephrologist, cardiologist, and/or primary care provider in the decision making process to reach a consensus and to ensure a safe follow-up plan.

The best answer is D. While A, B, and C are all reasonable approaches based on the available data and current guidelines, the best approach is to involve the patient and the multidisciplinary team in the decision making process. When more clinical trial data becomes available in the future, the optimal approach to managing patients such as this one may become clearer, but until then it makes sense to take into account individual patient characteristics and patient preferences.

SAN DIEGO – Whatever you do, don’t order a 24-hour urine test. Do encourage “pork holidays.” And choose between an ACE inhibitor and an ARB – don’t give them both to a single patient, according to Kim Zuber, PA-C, MS, a nephrology physician assistant from St. Petersburg, Fla., in a presentation about kidney disease, hypertension, and diabetes at the Metabolic & Endocrine Disease Summit, sponsored by Global Academy for Medical Education.

Ms. Zuber, who is the executive director of the American Academy of Nephrology PAs and the outreach chair of the National Kidney Foundation, outlined some approaches for the diagnosis, management, and treatment of chronic kidney disease (CKD) with comorbid hypertension and diabetes.

• Use the right urine test. Urine albumin testing, which detects albuminuria, is vital in patients who are at risk of chronic kidney disease, Ms. Zuber said, although it’s often not performed. In fact, research suggests that most Medicare patients with diabetes, hypertension, or both do not have this test, she said. Order a urine albumin-to-creatinine ratio (UACR) test at least once a year in at-risk patients, she recommended, and more frequently if they show signs of abnormal values. But be aware, she said, some labs might refer to the test as microalbuminuria instead of UACR, and be prepared to calculate the UACR yourself if your institution provides only albumin and creatinine levels. Also watch out for mix-ups regarding UACR measurements. Nephrotic-range proteinuria starts at 3 g/dL or 3,000 mg/dL, she said, and residents often confuse those two sets of units. “Many have gotten in trouble with that,” she said.
• Don’t go near a 24-hour urine test. Thinking about ordering a 24-hour urine test that requires a patients to collect all their urine for a day? Think again. “We’ve been telling you almost 20 years not to do this,” Ms. Zuber said. These tests “are unreliable, and they don’t work.”
• Don’t focus on tight blood pressure control. Studies provide little insight into the ideal blood pressure readings for patients with diabetes and CKD, according to Ms. Zuber, but some findings suggest that tight control can be harmful to the kidneys. She urges her patients to treat hypertension in part by embracing lifestyle change. “I tell them that if you improve your lifestyle, you can give up one of your drugs. When they average 15 drugs a day, that becomes popular.” Physical activity, the DASH diet, salt restriction, moderate alcohol consumption, weight loss, stress reduction, and smoking cessation can all lower blood pressure, she added.
• Talk up the “pork holiday.” For patients with hypertension, “sodium restriction is huge,” Ms. Zuber said, especially among black patients. She urges her patients to take “pork holidays”, that is, eat pork only four times a year, on holidays such as the Fourth of July. She also urges them to prepare food in ways that begin with B, as in bake, boil, and barbecue. “You’ll notice that ‘fry’ doesn’t start with a B.”
• Try an ACE inhibitor or an ARB, but not both. In patients with hypertension plus diabetes and/or CKD, Ms. Zuber suggests using an angiotensin-converting enzyme inhibitor or angiotensin receptor blockers, but not both. One or the other can improve albuminuria, she said, but together they can boost risk of CKD, hyperkalemia, and hypotension.

Consider factors such as formularies and personal experience when trying to decide which drug to use, she said. If a patient still has hypertension, consider a diuretic and then move to a calcium channel or beta blocker. However, she cautioned, although beta blockers, they can cause erectile dysfunction.

Global Academy for Medical Education and this news organization are owned by the same parent company. Ms. Zuber reported no disclosures.

SAN DIEGO – Whatever you do, don’t order a 24-hour urine test. Do encourage “pork holidays.” And choose between an ACE inhibitor and an ARB – don’t give them both to a single patient, according to Kim Zuber, PA-C, MS, a nephrology physician assistant from St. Petersburg, Fla., in a presentation about kidney disease, hypertension, and diabetes at the Metabolic & Endocrine Disease Summit, sponsored by Global Academy for Medical Education.

Ms. Zuber, who is the executive director of the American Academy of Nephrology PAs and the outreach chair of the National Kidney Foundation, outlined some approaches for the diagnosis, management, and treatment of chronic kidney disease (CKD) with comorbid hypertension and diabetes.

• Use the right urine test. Urine albumin testing, which detects albuminuria, is vital in patients who are at risk of chronic kidney disease, Ms. Zuber said, although it’s often not performed. In fact, research suggests that most Medicare patients with diabetes, hypertension, or both do not have this test, she said. Order a urine albumin-to-creatinine ratio (UACR) test at least once a year in at-risk patients, she recommended, and more frequently if they show signs of abnormal values. But be aware, she said, some labs might refer to the test as microalbuminuria instead of UACR, and be prepared to calculate the UACR yourself if your institution provides only albumin and creatinine levels. Also watch out for mix-ups regarding UACR measurements. Nephrotic-range proteinuria starts at 3 g/dL or 3,000 mg/dL, she said, and residents often confuse those two sets of units. “Many have gotten in trouble with that,” she said.
• Don’t go near a 24-hour urine test. Thinking about ordering a 24-hour urine test that requires a patients to collect all their urine for a day? Think again. “We’ve been telling you almost 20 years not to do this,” Ms. Zuber said. These tests “are unreliable, and they don’t work.”
• Don’t focus on tight blood pressure control. Studies provide little insight into the ideal blood pressure readings for patients with diabetes and CKD, according to Ms. Zuber, but some findings suggest that tight control can be harmful to the kidneys. She urges her patients to treat hypertension in part by embracing lifestyle change. “I tell them that if you improve your lifestyle, you can give up one of your drugs. When they average 15 drugs a day, that becomes popular.” Physical activity, the DASH diet, salt restriction, moderate alcohol consumption, weight loss, stress reduction, and smoking cessation can all lower blood pressure, she added.
• Talk up the “pork holiday.” For patients with hypertension, “sodium restriction is huge,” Ms. Zuber said, especially among black patients. She urges her patients to take “pork holidays”, that is, eat pork only four times a year, on holidays such as the Fourth of July. She also urges them to prepare food in ways that begin with B, as in bake, boil, and barbecue. “You’ll notice that ‘fry’ doesn’t start with a B.”
• Try an ACE inhibitor or an ARB, but not both. In patients with hypertension plus diabetes and/or CKD, Ms. Zuber suggests using an angiotensin-converting enzyme inhibitor or angiotensin receptor blockers, but not both. One or the other can improve albuminuria, she said, but together they can boost risk of CKD, hyperkalemia, and hypotension.

Consider factors such as formularies and personal experience when trying to decide which drug to use, she said. If a patient still has hypertension, consider a diuretic and then move to a calcium channel or beta blocker. However, she cautioned, although beta blockers, they can cause erectile dysfunction.

Global Academy for Medical Education and this news organization are owned by the same parent company. Ms. Zuber reported no disclosures.

SAN DIEGO – Whatever you do, don’t order a 24-hour urine test. Do encourage “pork holidays.” And choose between an ACE inhibitor and an ARB – don’t give them both to a single patient, according to Kim Zuber, PA-C, MS, a nephrology physician assistant from St. Petersburg, Fla., in a presentation about kidney disease, hypertension, and diabetes at the Metabolic & Endocrine Disease Summit, sponsored by Global Academy for Medical Education.

Ms. Zuber, who is the executive director of the American Academy of Nephrology PAs and the outreach chair of the National Kidney Foundation, outlined some approaches for the diagnosis, management, and treatment of chronic kidney disease (CKD) with comorbid hypertension and diabetes.

• Use the right urine test. Urine albumin testing, which detects albuminuria, is vital in patients who are at risk of chronic kidney disease, Ms. Zuber said, although it’s often not performed. In fact, research suggests that most Medicare patients with diabetes, hypertension, or both do not have this test, she said. Order a urine albumin-to-creatinine ratio (UACR) test at least once a year in at-risk patients, she recommended, and more frequently if they show signs of abnormal values. But be aware, she said, some labs might refer to the test as microalbuminuria instead of UACR, and be prepared to calculate the UACR yourself if your institution provides only albumin and creatinine levels. Also watch out for mix-ups regarding UACR measurements. Nephrotic-range proteinuria starts at 3 g/dL or 3,000 mg/dL, she said, and residents often confuse those two sets of units. “Many have gotten in trouble with that,” she said.
• Don’t go near a 24-hour urine test. Thinking about ordering a 24-hour urine test that requires a patients to collect all their urine for a day? Think again. “We’ve been telling you almost 20 years not to do this,” Ms. Zuber said. These tests “are unreliable, and they don’t work.”
• Don’t focus on tight blood pressure control. Studies provide little insight into the ideal blood pressure readings for patients with diabetes and CKD, according to Ms. Zuber, but some findings suggest that tight control can be harmful to the kidneys. She urges her patients to treat hypertension in part by embracing lifestyle change. “I tell them that if you improve your lifestyle, you can give up one of your drugs. When they average 15 drugs a day, that becomes popular.” Physical activity, the DASH diet, salt restriction, moderate alcohol consumption, weight loss, stress reduction, and smoking cessation can all lower blood pressure, she added.
• Talk up the “pork holiday.” For patients with hypertension, “sodium restriction is huge,” Ms. Zuber said, especially among black patients. She urges her patients to take “pork holidays”, that is, eat pork only four times a year, on holidays such as the Fourth of July. She also urges them to prepare food in ways that begin with B, as in bake, boil, and barbecue. “You’ll notice that ‘fry’ doesn’t start with a B.”
• Try an ACE inhibitor or an ARB, but not both. In patients with hypertension plus diabetes and/or CKD, Ms. Zuber suggests using an angiotensin-converting enzyme inhibitor or angiotensin receptor blockers, but not both. One or the other can improve albuminuria, she said, but together they can boost risk of CKD, hyperkalemia, and hypotension.

Consider factors such as formularies and personal experience when trying to decide which drug to use, she said. If a patient still has hypertension, consider a diuretic and then move to a calcium channel or beta blocker. However, she cautioned, although beta blockers, they can cause erectile dysfunction.

Global Academy for Medical Education and this news organization are owned by the same parent company. Ms. Zuber reported no disclosures.

In a study from the University of Pennsylvania,² Sedrak et al surveyed residents about their lab test ordering practices. Almost all responders recognized that they ordered “unnecessary tests.” The authors of the paper probed to understand why, and strikingly, the more common responses were the same that my resident peers and I would have given 4 decades ago: the culture of the system (“We don’t want to miss anything or be asked on rounds for data that hadn’t been checked”), the lack of transparency of cost of the tests, and the lack of role-modeling by teaching staff. There has been hope that the last of these would be resolved by increased visibility of subspecialists in hospital medicine, well-versed in the nuances of system-based practice. And the Society of Hospital Medicine, along with the American College of Physicians and others, has pushed hard to promote choosing wisely when ordering diagnostic studies. But we have a way to go.

Lab tests represent a small fraction of healthcare costs. Imaging tests, especially advanced and complex imaging studies, comprise a far greater fraction of healthcare costs. And here is the challenge: developers of new imaging modalities are now able to design and refine specific tests that are good enough to become the gold standard for diagnosis and staging of specific diseases—great for clinical care, bad for cost savings. One need only review a few new guidelines or clinical research protocols to appreciate the successful integration of these tests into clinical practice. Some tests are supplanting the need for aggressive biopsies, angiography, or a series of alternative imaging tests. This is potentially good for patients, but many of these tests are strikingly expensive and are being adopted for use prior to full vetting of their utility and limitations in large clinical studies; the cost of the tests can be an impediment to conducting a series of clinical studies that include appropriate patient subsets. The increasingly proposed use of positron emission tomography in patients with suspected malignancy, inflammation, or infection is a great example of a useful test that we are still learning how best to interpret in several conditions.

In this issue of the Journal, two testing scenarios are discussed. Lacy et al address the question of when patients with pyelonephritis should receive imaging studies. There are data to guide this decision process, but as noted in the study by Sedrak et al,² there are forces at work that challenge the clinician to bypass the rational guidelines—not the least of which are the desire for efficiency (don’t take the chance that the test may be required later and delay discharge from the hospital or observation area) and greater surety in the clinical diagnosis. Although fear of litigation was not high on Sedrak’s list of reasons for ordering more “unnecessary” tests, I posit that a decrease in the confidence placed on clinical diagnosis drives a significant amount of imaging, in conjunction with the desire for shorter hospital stays.

The second paper, by Mgbojikwe et al, relates to the issue of which advanced technology should be ordered, and when. They review the limitations of traditional (echocardiographic) diagnosis and staging of infective endocarditis, and discuss the strengths and limitations of several advanced imaging tools in the setting of suspected or known infectious endocarditis. I suspect that in most medical centers the decisions to utilize these tests will rest with the infectious disease, cardiology, and cardiothoracic surgery consultants. But it is worth being aware of how the diagnostic and staging strategies are evolving, and of the limitations to these studies.

We have come a long way from diagnosing bacterial endocarditis with a valve abscess on the basis of finding changing murmurs, a Roth spot, a palpable spleen tip, new conduction abnormalities on the ECG, and documented daily afternoon fevers. Performing that physical examination is cheap but not highly reproducible. The new testing algorithms are not cheap but, hopefully, will offer superior sensitivity and specificity. Used correctly—and we likely have a way to go to learn what that means—these pictures may well be worth the cost.

Although someone still has to suspect the diagnosis of endocarditis.

In a study from the University of Pennsylvania,² Sedrak et al surveyed residents about their lab test ordering practices. Almost all responders recognized that they ordered “unnecessary tests.” The authors of the paper probed to understand why, and strikingly, the more common responses were the same that my resident peers and I would have given 4 decades ago: the culture of the system (“We don’t want to miss anything or be asked on rounds for data that hadn’t been checked”), the lack of transparency of cost of the tests, and the lack of role-modeling by teaching staff. There has been hope that the last of these would be resolved by increased visibility of subspecialists in hospital medicine, well-versed in the nuances of system-based practice. And the Society of Hospital Medicine, along with the American College of Physicians and others, has pushed hard to promote choosing wisely when ordering diagnostic studies. But we have a way to go.

Lab tests represent a small fraction of healthcare costs. Imaging tests, especially advanced and complex imaging studies, comprise a far greater fraction of healthcare costs. And here is the challenge: developers of new imaging modalities are now able to design and refine specific tests that are good enough to become the gold standard for diagnosis and staging of specific diseases—great for clinical care, bad for cost savings. One need only review a few new guidelines or clinical research protocols to appreciate the successful integration of these tests into clinical practice. Some tests are supplanting the need for aggressive biopsies, angiography, or a series of alternative imaging tests. This is potentially good for patients, but many of these tests are strikingly expensive and are being adopted for use prior to full vetting of their utility and limitations in large clinical studies; the cost of the tests can be an impediment to conducting a series of clinical studies that include appropriate patient subsets. The increasingly proposed use of positron emission tomography in patients with suspected malignancy, inflammation, or infection is a great example of a useful test that we are still learning how best to interpret in several conditions.

In this issue of the Journal, two testing scenarios are discussed. Lacy et al address the question of when patients with pyelonephritis should receive imaging studies. There are data to guide this decision process, but as noted in the study by Sedrak et al,² there are forces at work that challenge the clinician to bypass the rational guidelines—not the least of which are the desire for efficiency (don’t take the chance that the test may be required later and delay discharge from the hospital or observation area) and greater surety in the clinical diagnosis. Although fear of litigation was not high on Sedrak’s list of reasons for ordering more “unnecessary” tests, I posit that a decrease in the confidence placed on clinical diagnosis drives a significant amount of imaging, in conjunction with the desire for shorter hospital stays.

The second paper, by Mgbojikwe et al, relates to the issue of which advanced technology should be ordered, and when. They review the limitations of traditional (echocardiographic) diagnosis and staging of infective endocarditis, and discuss the strengths and limitations of several advanced imaging tools in the setting of suspected or known infectious endocarditis. I suspect that in most medical centers the decisions to utilize these tests will rest with the infectious disease, cardiology, and cardiothoracic surgery consultants. But it is worth being aware of how the diagnostic and staging strategies are evolving, and of the limitations to these studies.

We have come a long way from diagnosing bacterial endocarditis with a valve abscess on the basis of finding changing murmurs, a Roth spot, a palpable spleen tip, new conduction abnormalities on the ECG, and documented daily afternoon fevers. Performing that physical examination is cheap but not highly reproducible. The new testing algorithms are not cheap but, hopefully, will offer superior sensitivity and specificity. Used correctly—and we likely have a way to go to learn what that means—these pictures may well be worth the cost.

Although someone still has to suspect the diagnosis of endocarditis.

In a study from the University of Pennsylvania,² Sedrak et al surveyed residents about their lab test ordering practices. Almost all responders recognized that they ordered “unnecessary tests.” The authors of the paper probed to understand why, and strikingly, the more common responses were the same that my resident peers and I would have given 4 decades ago: the culture of the system (“We don’t want to miss anything or be asked on rounds for data that hadn’t been checked”), the lack of transparency of cost of the tests, and the lack of role-modeling by teaching staff. There has been hope that the last of these would be resolved by increased visibility of subspecialists in hospital medicine, well-versed in the nuances of system-based practice. And the Society of Hospital Medicine, along with the American College of Physicians and others, has pushed hard to promote choosing wisely when ordering diagnostic studies. But we have a way to go.

Lab tests represent a small fraction of healthcare costs. Imaging tests, especially advanced and complex imaging studies, comprise a far greater fraction of healthcare costs. And here is the challenge: developers of new imaging modalities are now able to design and refine specific tests that are good enough to become the gold standard for diagnosis and staging of specific diseases—great for clinical care, bad for cost savings. One need only review a few new guidelines or clinical research protocols to appreciate the successful integration of these tests into clinical practice. Some tests are supplanting the need for aggressive biopsies, angiography, or a series of alternative imaging tests. This is potentially good for patients, but many of these tests are strikingly expensive and are being adopted for use prior to full vetting of their utility and limitations in large clinical studies; the cost of the tests can be an impediment to conducting a series of clinical studies that include appropriate patient subsets. The increasingly proposed use of positron emission tomography in patients with suspected malignancy, inflammation, or infection is a great example of a useful test that we are still learning how best to interpret in several conditions.

In this issue of the Journal, two testing scenarios are discussed. Lacy et al address the question of when patients with pyelonephritis should receive imaging studies. There are data to guide this decision process, but as noted in the study by Sedrak et al,² there are forces at work that challenge the clinician to bypass the rational guidelines—not the least of which are the desire for efficiency (don’t take the chance that the test may be required later and delay discharge from the hospital or observation area) and greater surety in the clinical diagnosis. Although fear of litigation was not high on Sedrak’s list of reasons for ordering more “unnecessary” tests, I posit that a decrease in the confidence placed on clinical diagnosis drives a significant amount of imaging, in conjunction with the desire for shorter hospital stays.

The second paper, by Mgbojikwe et al, relates to the issue of which advanced technology should be ordered, and when. They review the limitations of traditional (echocardiographic) diagnosis and staging of infective endocarditis, and discuss the strengths and limitations of several advanced imaging tools in the setting of suspected or known infectious endocarditis. I suspect that in most medical centers the decisions to utilize these tests will rest with the infectious disease, cardiology, and cardiothoracic surgery consultants. But it is worth being aware of how the diagnostic and staging strategies are evolving, and of the limitations to these studies.

We have come a long way from diagnosing bacterial endocarditis with a valve abscess on the basis of finding changing murmurs, a Roth spot, a palpable spleen tip, new conduction abnormalities on the ECG, and documented daily afternoon fevers. Performing that physical examination is cheap but not highly reproducible. The new testing algorithms are not cheap but, hopefully, will offer superior sensitivity and specificity. Used correctly—and we likely have a way to go to learn what that means—these pictures may well be worth the cost.

Although someone still has to suspect the diagnosis of endocarditis.

A previously healthy 44-year-old woman presents to the emergency department with 1 day of fever, flank pain, dysuria, and persistent nausea and vomiting. Her temperature is 38.7°C (101.7°F), heart rate 102 beats per minute, and blood pressure 120/70 mm Hg. She has costovertebral angle tenderness. Laboratory testing reveals mild leukocytosis and a normal serum creatinine level; urinalysis shows leukocytes, as well as leukocyte esterase and nitrites. She has no personal or family history of nephrolithiasis. Urine cultures are obtained, and she is started on intravenous antibiotics and intravenous hydration to treat pyelonephritis.

Is imaging indicated at this point? And if so, which study is recommended?

KEY FEATURES

Acute pyelonephritis, infection of the renal parenchyma and collecting system, most often results from an ascending infection of the lower urinary tract. It is estimated to account for 250,000 office visits and 200,000 hospital admissions each year in the United States.¹

Lower urinary tract symptoms such as urinary frequency, urgency, and dysuria accompanied by fever, nausea, vomiting, and flank pain raise suspicion for acute pyelonephritis. Flank pain is a key, nearly universal feature of upper urinary tract infection in patients without diabetes, though it may be absent in up to 50% of patients with diabetes.²

Additional findings include costovertebral angle tenderness on physical examination and leukocytosis, pyuria, and bacteriuria on laboratory studies.

PREDICTING THE NEED FOR EARLY IMAGING

Though guidelines state that imaging is inappropriate in most patients with pyeloneph­ritis,^2–4 it is nevertheless often done for diagnosis or identification of complications, which have been reported in more than two-thirds of patients.^2–4

Acute pyelonephritis is generally classified as complicated or uncomplicated, though different definitions exist with regard to these classifications. The American College of Radiology’s Appropriateness Criteria2 consider patients with diabetes, immune compromise, a history of urolithiasis, or anatomic abnormality to be at highest risk for complications, and therefore recommend early imaging to assess for hydronephrosis, pyonephrosis, emphysematous pyelonephritis, and intrinsic or perinephric abscess.²

A clinical rule for predicting the need for imaging in acute pyelonephritis was developed and validated in an emergency department population in the Netherlands.³ The study suggested that restricting early imaging to patients with a history of urolithiasis, a urine pH of 7.0 or higher, or renal insufficiency—defined as a glomerular filtration rate (GFR) of 40 mL/min/1.73m² or lower as estimated by the Modification of Diet in Renal Disease formula—would provide a negative predictive value of 94% to 100% for detection of an urgent urologic disorder (pyonephrosis, renal abscess, or urolithiasis). This high negative predictive value highlights that an absence of these signs and symptoms can safely identify patients who do not need renal imaging.

The positive predictive value was less useful, as only 5% to 23% of patients who had at least 1 risk factor went on to have urgent urologic risk factors.³

Implementation of this prediction rule would have resulted in a relative reduction in imaging of 40% and an absolute reduction of 28%. Of note, use of reduced GFR in this prediction rule is not clearly validated for patients with chronic kidney disease, as the previous GFR for most patients in this study was unknown.³

Based on these data, initial imaging is recommended in patients with diabetes, immune compromise, a history of urolithiasis, anatomic abnormality, a urine pH 7.0 or higher, or a GFR 40 mL/min or lower in a patient with no history of significant renal dysfunction. Early imaging would also be reasonable in patients with a complex clinical presentation, early recurrence of symptoms after treatment, clinical decompensation, or critical illness.

In a retrospective review of 62 patients hospitalized for acute renal infection, Soulen et al5 found that the most reliable indicator of complicated acute pyelonephritis was the persistence of fever and leukocytosis at 72 hours. And another small prospective study of patients with uncomplicated pyelonephritis reported a time to defervescence of no more than 4 days.⁶

In accordance with the Appropriateness Criteria2 and based on the best available evidence, imaging is recommended in all patients who remain febrile or have persistent leukocytosis after 72 hours of antibiotic therapy. In such cases, there should be high suspicion for a complication requiring treatment.

OPTIONS FOR IMAGING

Computed tomography

Computed tomography (CT) of the abdomen and pelvis with contrast is considered the study of choice in complicated acute pyelonephritis. CT can detect focal parenchymal abnormalities, emphysematous changes, and anatomic anomalies, and can also define the extent of disease. It can also detect perinephric fluid collections and abscesses that necessitate a change in management.^2,5

A retrospective study in 2017 found that contrast-enhanced CT done without the usual noncontrast and excretory phases had an accuracy of 90% to 92% for pyelonephritis and 96% to 99% for urolithiasis, suggesting that reduction in radiation exposure through use of only the contrast-enhanced phase of CT imaging may be reasonable.⁷

Magnetic resonance imaging

Magnetic resonance imaging (MRI) is increasingly acknowledged as effective in the evaluation of renal pathology, including the diagnosis of pyelonephritis; but it lacks the level of evidence that CT provides for detecting renal abscesses, calculi, and emphysematous pyelonephritis.^2,8,9

Though it is more costly and time-consuming than CT with contrast enhancement, MRI is nevertheless the imaging study of choice if iodinated contrast or ionizing radiation must be avoided.

MRI typically involves a precontrast phase and a gadolinium contrast-enhanced phase, though there are data to support diffusion-weighted MRI when exposure to gadolinium poses a risk to the patient, such as in pregnancy or renal impairment (particularly when the estimated GFR is < 30 mL/min/1.73 m²).¹⁰

Ultrasonography

Conventional ultrasonography is appealing due to its relatively low cost, its availability and portability, and the lack of radiation and contrast exposure. It is most helpful in detecting hydronephrosis and pyonephrosis rather than intrarenal or perinephric abscess.^2,9

Color and power Doppler ultrasonography may improve testing characteristics but not to the level of CT; in one study, sensitivity for detection of pyelonephritis was 33.3% with ultrasonography vs 81.0% with CT.¹¹

Recent studies of ultrasonography with contrast enhancement show promising results,² and it may ultimately prove to have a similar efficacy with lower risk for patients, but this has not been validated in large studies, and its availability remains limited.

Ultrasonography should be considered for patients in whom obstruction (with resulting hydronephrosis or pyonephrosis) is a primary concern, particularly when contrast exposure or radiation is contraindicated and MRI is unavailable.²

Abdominal radiography

While emphysematous pyelonephritis or a large staghorn calculus may be seen on abdominal radiography, it is not recommended for the assessment of complications in acute pyelonephritis because it lacks sensitivity.²

RETURN TO THE CASE SCENARIO

The patient in our case scenario meets the clinical criteria for uncomplicated pyelo­nephritis and is therefore not a candidate for imaging. Intravenous antibiotics should be started and should lead to rapid improvement in her condition.

Acknowledgment: The authors would like to thank Dr. Lisa Blacklock for her review of the radiology section of this paper.

A previously healthy 44-year-old woman presents to the emergency department with 1 day of fever, flank pain, dysuria, and persistent nausea and vomiting. Her temperature is 38.7°C (101.7°F), heart rate 102 beats per minute, and blood pressure 120/70 mm Hg. She has costovertebral angle tenderness. Laboratory testing reveals mild leukocytosis and a normal serum creatinine level; urinalysis shows leukocytes, as well as leukocyte esterase and nitrites. She has no personal or family history of nephrolithiasis. Urine cultures are obtained, and she is started on intravenous antibiotics and intravenous hydration to treat pyelonephritis.

Is imaging indicated at this point? And if so, which study is recommended?

KEY FEATURES

Acute pyelonephritis, infection of the renal parenchyma and collecting system, most often results from an ascending infection of the lower urinary tract. It is estimated to account for 250,000 office visits and 200,000 hospital admissions each year in the United States.¹

Lower urinary tract symptoms such as urinary frequency, urgency, and dysuria accompanied by fever, nausea, vomiting, and flank pain raise suspicion for acute pyelonephritis. Flank pain is a key, nearly universal feature of upper urinary tract infection in patients without diabetes, though it may be absent in up to 50% of patients with diabetes.²

Additional findings include costovertebral angle tenderness on physical examination and leukocytosis, pyuria, and bacteriuria on laboratory studies.

PREDICTING THE NEED FOR EARLY IMAGING

Though guidelines state that imaging is inappropriate in most patients with pyeloneph­ritis,^2–4 it is nevertheless often done for diagnosis or identification of complications, which have been reported in more than two-thirds of patients.^2–4

Acute pyelonephritis is generally classified as complicated or uncomplicated, though different definitions exist with regard to these classifications. The American College of Radiology’s Appropriateness Criteria2 consider patients with diabetes, immune compromise, a history of urolithiasis, or anatomic abnormality to be at highest risk for complications, and therefore recommend early imaging to assess for hydronephrosis, pyonephrosis, emphysematous pyelonephritis, and intrinsic or perinephric abscess.²

A clinical rule for predicting the need for imaging in acute pyelonephritis was developed and validated in an emergency department population in the Netherlands.³ The study suggested that restricting early imaging to patients with a history of urolithiasis, a urine pH of 7.0 or higher, or renal insufficiency—defined as a glomerular filtration rate (GFR) of 40 mL/min/1.73m² or lower as estimated by the Modification of Diet in Renal Disease formula—would provide a negative predictive value of 94% to 100% for detection of an urgent urologic disorder (pyonephrosis, renal abscess, or urolithiasis). This high negative predictive value highlights that an absence of these signs and symptoms can safely identify patients who do not need renal imaging.

The positive predictive value was less useful, as only 5% to 23% of patients who had at least 1 risk factor went on to have urgent urologic risk factors.³

Implementation of this prediction rule would have resulted in a relative reduction in imaging of 40% and an absolute reduction of 28%. Of note, use of reduced GFR in this prediction rule is not clearly validated for patients with chronic kidney disease, as the previous GFR for most patients in this study was unknown.³

Based on these data, initial imaging is recommended in patients with diabetes, immune compromise, a history of urolithiasis, anatomic abnormality, a urine pH 7.0 or higher, or a GFR 40 mL/min or lower in a patient with no history of significant renal dysfunction. Early imaging would also be reasonable in patients with a complex clinical presentation, early recurrence of symptoms after treatment, clinical decompensation, or critical illness.

In a retrospective review of 62 patients hospitalized for acute renal infection, Soulen et al5 found that the most reliable indicator of complicated acute pyelonephritis was the persistence of fever and leukocytosis at 72 hours. And another small prospective study of patients with uncomplicated pyelonephritis reported a time to defervescence of no more than 4 days.⁶

In accordance with the Appropriateness Criteria2 and based on the best available evidence, imaging is recommended in all patients who remain febrile or have persistent leukocytosis after 72 hours of antibiotic therapy. In such cases, there should be high suspicion for a complication requiring treatment.

OPTIONS FOR IMAGING

Computed tomography

Computed tomography (CT) of the abdomen and pelvis with contrast is considered the study of choice in complicated acute pyelonephritis. CT can detect focal parenchymal abnormalities, emphysematous changes, and anatomic anomalies, and can also define the extent of disease. It can also detect perinephric fluid collections and abscesses that necessitate a change in management.^2,5

A retrospective study in 2017 found that contrast-enhanced CT done without the usual noncontrast and excretory phases had an accuracy of 90% to 92% for pyelonephritis and 96% to 99% for urolithiasis, suggesting that reduction in radiation exposure through use of only the contrast-enhanced phase of CT imaging may be reasonable.⁷

Magnetic resonance imaging

Magnetic resonance imaging (MRI) is increasingly acknowledged as effective in the evaluation of renal pathology, including the diagnosis of pyelonephritis; but it lacks the level of evidence that CT provides for detecting renal abscesses, calculi, and emphysematous pyelonephritis.^2,8,9

Though it is more costly and time-consuming than CT with contrast enhancement, MRI is nevertheless the imaging study of choice if iodinated contrast or ionizing radiation must be avoided.

MRI typically involves a precontrast phase and a gadolinium contrast-enhanced phase, though there are data to support diffusion-weighted MRI when exposure to gadolinium poses a risk to the patient, such as in pregnancy or renal impairment (particularly when the estimated GFR is < 30 mL/min/1.73 m²).¹⁰

Ultrasonography

Conventional ultrasonography is appealing due to its relatively low cost, its availability and portability, and the lack of radiation and contrast exposure. It is most helpful in detecting hydronephrosis and pyonephrosis rather than intrarenal or perinephric abscess.^2,9

Color and power Doppler ultrasonography may improve testing characteristics but not to the level of CT; in one study, sensitivity for detection of pyelonephritis was 33.3% with ultrasonography vs 81.0% with CT.¹¹

Recent studies of ultrasonography with contrast enhancement show promising results,² and it may ultimately prove to have a similar efficacy with lower risk for patients, but this has not been validated in large studies, and its availability remains limited.

Ultrasonography should be considered for patients in whom obstruction (with resulting hydronephrosis or pyonephrosis) is a primary concern, particularly when contrast exposure or radiation is contraindicated and MRI is unavailable.²

Abdominal radiography

While emphysematous pyelonephritis or a large staghorn calculus may be seen on abdominal radiography, it is not recommended for the assessment of complications in acute pyelonephritis because it lacks sensitivity.²

RETURN TO THE CASE SCENARIO

The patient in our case scenario meets the clinical criteria for uncomplicated pyelo­nephritis and is therefore not a candidate for imaging. Intravenous antibiotics should be started and should lead to rapid improvement in her condition.

Acknowledgment: The authors would like to thank Dr. Lisa Blacklock for her review of the radiology section of this paper.

A previously healthy 44-year-old woman presents to the emergency department with 1 day of fever, flank pain, dysuria, and persistent nausea and vomiting. Her temperature is 38.7°C (101.7°F), heart rate 102 beats per minute, and blood pressure 120/70 mm Hg. She has costovertebral angle tenderness. Laboratory testing reveals mild leukocytosis and a normal serum creatinine level; urinalysis shows leukocytes, as well as leukocyte esterase and nitrites. She has no personal or family history of nephrolithiasis. Urine cultures are obtained, and she is started on intravenous antibiotics and intravenous hydration to treat pyelonephritis.

Is imaging indicated at this point? And if so, which study is recommended?

KEY FEATURES

Acute pyelonephritis, infection of the renal parenchyma and collecting system, most often results from an ascending infection of the lower urinary tract. It is estimated to account for 250,000 office visits and 200,000 hospital admissions each year in the United States.¹

Lower urinary tract symptoms such as urinary frequency, urgency, and dysuria accompanied by fever, nausea, vomiting, and flank pain raise suspicion for acute pyelonephritis. Flank pain is a key, nearly universal feature of upper urinary tract infection in patients without diabetes, though it may be absent in up to 50% of patients with diabetes.²

Additional findings include costovertebral angle tenderness on physical examination and leukocytosis, pyuria, and bacteriuria on laboratory studies.

PREDICTING THE NEED FOR EARLY IMAGING

Though guidelines state that imaging is inappropriate in most patients with pyeloneph­ritis,^2–4 it is nevertheless often done for diagnosis or identification of complications, which have been reported in more than two-thirds of patients.^2–4

Acute pyelonephritis is generally classified as complicated or uncomplicated, though different definitions exist with regard to these classifications. The American College of Radiology’s Appropriateness Criteria2 consider patients with diabetes, immune compromise, a history of urolithiasis, or anatomic abnormality to be at highest risk for complications, and therefore recommend early imaging to assess for hydronephrosis, pyonephrosis, emphysematous pyelonephritis, and intrinsic or perinephric abscess.²

A clinical rule for predicting the need for imaging in acute pyelonephritis was developed and validated in an emergency department population in the Netherlands.³ The study suggested that restricting early imaging to patients with a history of urolithiasis, a urine pH of 7.0 or higher, or renal insufficiency—defined as a glomerular filtration rate (GFR) of 40 mL/min/1.73m² or lower as estimated by the Modification of Diet in Renal Disease formula—would provide a negative predictive value of 94% to 100% for detection of an urgent urologic disorder (pyonephrosis, renal abscess, or urolithiasis). This high negative predictive value highlights that an absence of these signs and symptoms can safely identify patients who do not need renal imaging.

The positive predictive value was less useful, as only 5% to 23% of patients who had at least 1 risk factor went on to have urgent urologic risk factors.³

Implementation of this prediction rule would have resulted in a relative reduction in imaging of 40% and an absolute reduction of 28%. Of note, use of reduced GFR in this prediction rule is not clearly validated for patients with chronic kidney disease, as the previous GFR for most patients in this study was unknown.³

Based on these data, initial imaging is recommended in patients with diabetes, immune compromise, a history of urolithiasis, anatomic abnormality, a urine pH 7.0 or higher, or a GFR 40 mL/min or lower in a patient with no history of significant renal dysfunction. Early imaging would also be reasonable in patients with a complex clinical presentation, early recurrence of symptoms after treatment, clinical decompensation, or critical illness.

In a retrospective review of 62 patients hospitalized for acute renal infection, Soulen et al5 found that the most reliable indicator of complicated acute pyelonephritis was the persistence of fever and leukocytosis at 72 hours. And another small prospective study of patients with uncomplicated pyelonephritis reported a time to defervescence of no more than 4 days.⁶

In accordance with the Appropriateness Criteria2 and based on the best available evidence, imaging is recommended in all patients who remain febrile or have persistent leukocytosis after 72 hours of antibiotic therapy. In such cases, there should be high suspicion for a complication requiring treatment.

OPTIONS FOR IMAGING

Computed tomography

Computed tomography (CT) of the abdomen and pelvis with contrast is considered the study of choice in complicated acute pyelonephritis. CT can detect focal parenchymal abnormalities, emphysematous changes, and anatomic anomalies, and can also define the extent of disease. It can also detect perinephric fluid collections and abscesses that necessitate a change in management.^2,5

A retrospective study in 2017 found that contrast-enhanced CT done without the usual noncontrast and excretory phases had an accuracy of 90% to 92% for pyelonephritis and 96% to 99% for urolithiasis, suggesting that reduction in radiation exposure through use of only the contrast-enhanced phase of CT imaging may be reasonable.⁷

Magnetic resonance imaging

Magnetic resonance imaging (MRI) is increasingly acknowledged as effective in the evaluation of renal pathology, including the diagnosis of pyelonephritis; but it lacks the level of evidence that CT provides for detecting renal abscesses, calculi, and emphysematous pyelonephritis.^2,8,9

Though it is more costly and time-consuming than CT with contrast enhancement, MRI is nevertheless the imaging study of choice if iodinated contrast or ionizing radiation must be avoided.

MRI typically involves a precontrast phase and a gadolinium contrast-enhanced phase, though there are data to support diffusion-weighted MRI when exposure to gadolinium poses a risk to the patient, such as in pregnancy or renal impairment (particularly when the estimated GFR is < 30 mL/min/1.73 m²).¹⁰

Ultrasonography

Conventional ultrasonography is appealing due to its relatively low cost, its availability and portability, and the lack of radiation and contrast exposure. It is most helpful in detecting hydronephrosis and pyonephrosis rather than intrarenal or perinephric abscess.^2,9

Color and power Doppler ultrasonography may improve testing characteristics but not to the level of CT; in one study, sensitivity for detection of pyelonephritis was 33.3% with ultrasonography vs 81.0% with CT.¹¹

Recent studies of ultrasonography with contrast enhancement show promising results,² and it may ultimately prove to have a similar efficacy with lower risk for patients, but this has not been validated in large studies, and its availability remains limited.

Ultrasonography should be considered for patients in whom obstruction (with resulting hydronephrosis or pyonephrosis) is a primary concern, particularly when contrast exposure or radiation is contraindicated and MRI is unavailable.²

Abdominal radiography

While emphysematous pyelonephritis or a large staghorn calculus may be seen on abdominal radiography, it is not recommended for the assessment of complications in acute pyelonephritis because it lacks sensitivity.²

RETURN TO THE CASE SCENARIO

The patient in our case scenario meets the clinical criteria for uncomplicated pyelo­nephritis and is therefore not a candidate for imaging. Intravenous antibiotics should be started and should lead to rapid improvement in her condition.

Acknowledgment: The authors would like to thank Dr. Lisa Blacklock for her review of the radiology section of this paper.