Dabigatran, rivaroxaban prescriptions increasing for dialysis patients with afib

More patients with atrial fibrillation who also receive hemodialysis are being prescribed dabigatran and rivaroxaban despite contraindications, according to a new study.

Dabigatran and rivaroxaban have not been studied in patients with end-stage renal disease, and their use in this population is contraindicated because they are cleared through the kidneys and can increase bleeding risk. Researchers used a U.S. database of patients receiving chronic dialysis to examine the prevalence of dabigatran and rivaroxaban prescriptions in those with atrial fibrillation from October 2010 to October 2014. Bleeding rates in patients taking warfarin, dabigatran, or rivaroxaban were also compared. Patients were followed for stroke and bleeding outcomes for up to 2 years. The study results were published online Jan. 16 by Circulation.

A total of 29,977 hemodialysis patients with atrial fibrillation were included in the study. The authors found that since dabigatran and rivaroxaban became available in the U.S., the prescription rate in patients with atrial fibrillation and end-stage renal disease has increased steadily; by 2014, the prevalence of dabigatran and rivaroxaban prescription in the study population was 4.6 per 100 patients. Dabigatran (relative risk, 1.48 [95% CI, 1.21 to 1.81; P<0.0001]) and rivaroxaban (relative risk, 1.38 [95% CI, 1.03 to 1.83; P=0.04]) were associated with a higher risk of major bleeding than warfarin, as well as a higher risk for hemorrhagic death (relative risk, 1.78 [95% CI, 1.18 to 2.68; P=0.006] and 1.71 [95% CI, 0.94 to 3.12; P=0.07], respectively). Differences in stroke and arterial embolism could not be detected between the groups because these events were uncommon.

The authors noted that their analysis for cerebrovascular events was underpowered, that they did not have data available on blood transfusion, and that confounding by indication was possible, among other limitations. However, they concluded that dialysis patients in the U.S. are increasingly being prescribed dabigatran and rivaroxaban even though these drugs are contraindicated in patients with end-stage renal disease. They noted that dabigatran and rivaroxaban were first prescribed to patients in the study database 45 days and 161 days, respectively, after their FDA approval and that the increased use of both drugs in patients with end-stage renal disease is occurring “despite formal FDA warnings of caution in renal failure.” More research on the safety and efficacy of these new oral anticoagulants in patients with end-stage renal disease is necessary, but they should not currently be used in those on dialysis, the authors wrote.