Apixaban vs warfarin in patients with nonvalvular atrial fibrillation receiving dialysis

Atrial fibrillation (AF) is common in people with kidney failure receiving dialysis, and recently direct oral anticoagulants have become a popular choice over warfarin because they act quickly, have comparatively fewer drug interactions, and do not require regular laboratory monitoring. Furthermore, in the general population, they are as effective in stroke prevention and have a lower risk of bleeding, compared to warfarin.

This US-based retrospective cohort study included 17,156 patients with nonvalvular AF receiving maintenance dialysis and who were prescribed an anticoagulant. The clinical outcome measures were incidence of ischaemic stroke/systemic embolism, major bleeding, and all-cause mortality. The majority of the cohort (73%) received warfarin, approximately 14% received label-concordant apixaban and a further 13% received below-label apixaban.

Intention-to-treat analysis revealed that neither label-concordant (HR,0.89 [95% CI, 0.65-1.21]) nor below-label (HR, 0.85[95% CI, 0.62-1.17]) apixaban dosing were associated with a difference in the risk of stroke/systemic embolism, compared with warfarin. Furthermore, both label-concordant (HR, 0.67 [95% CI, 0.55-0.81]) and below-label (HR, 0.68 [95% CI, 0.55-0.84]) apixaban dosing were associated with a lower risk of major bleeding, compared with warfarin. Finally, intention-to-treat analysis showed that label-concordant apixaban dosing was associated with a decreased risk of all-cause mortality.

The authors suggest that, based on these analyses, there may be a mortality benefit for apixaban relative to warfarin in the dialysis population with nonvalvular AF and that there was no difference in bleeding risks between label-concordant and below-label apixaban dosing. Clearly, this needs testing in properly designed prospective studies, but it is useful information for clinicians and patients who ae considering, or already using apixaban off-licence in UK-based patients on dialysis.

The full study can be read here.