For dialysis patients with nonvalvular atrial fibrillation (AF), anti-coagulation with apixaban—at both standard and below-label doses—lowers the risk of bleeding events compared with warfarin, concludes a study in the American Journal of Kidney Diseases.
Using US Renal Data System data from 2013 to 2018, the researchers identified 17,156 Medicare beneficiaries with nonvalvular AF receiving maintenance hemodialysis. All patients (12,517) had a new prescription for warfarin, and 2382 patients had apixaban at a label-concordant dose of 5 mg twice daily, or 2257 patients had apixaban at a lower dose of 2.5 mg twice daily. Outcomes, including stroke or systemic embolism, major bleeding events, and death from any cause, were compared between apixaban groups. The mean age of patients was 66 years, and 38% of patients were women, 68% were White, and 28% were Black. The percentage receiving warfarin decreased from 86% in 2014 (the year apixaban was approved) to 42% in 2018.
Risk of stroke or systemic embolism was similar across treatment groups: approximately 2 per 100 patient-years with approaches designed to simulate intention-to-treat (ITT) analysis and to incorporate censoring at drug switch or discontinuation (CAS). However, apixaban was associated with a lower rate of major bleeding events. In the ITT analysis, hazard ratios (HRs) were 0.67 with label-concordant dosing and 0.68 with below-label dosing. In the CAS analysis, HRs were 0.53 and 0.562, respectively. Label-concordant apixaban was also associated with lower all-cause mortality: HR was 0.85 with both ITT and CAS analyses. There was no difference in mortality with below-label apixaban versus warfarin.
Nonvalvular AF is common in dialysis patients, and anti-coagulants are prescribed to reduce the risk of stroke. In this group of patients, the direct oral anti-coagulant apixaban is sometimes given at below-label doses to reduce bleeding risks. There are limited data to guide anti-coagulant treatment in dialysis patients with AF.
This analysis suggests that apixaban reduces the risk of major bleeding, compared with warfarin, in dialysis patients with nonvalvular AF. Bleeding risk is similar for label-concordant and below-label dosing, whereas the standard dose appears to be associated with lower mortality. The investigators conclude, “Label-concordant apixaban dosing may therefore provide the best tradeoff of benefits and risks among the treatment approaches assessed” [Wetmore JB, et al. Apixaban dosing patterns versus warfarin in patients with nonvalvular atrial fibrillation receiving dialysis: A retrospective cohort study. Am J Kidney Dis, published online ahead of print April 22, 2022. doi: 10.1053/j.ajkd.2022.03.007; https://www.ajkd.org/article/S0272-6386(22)00621-7/fulltext].
