CKD Progression in Medicare Beneficiaries With Nonvalvular Atrial Fibrillation Treated With Apixaban Versus Warfarin.

Abstract

RATIONALE & OBJECTIVES\nComparing kidney disease progression among patients treated with direct oral anticoagulants (DOACs) versus warfarin has not been well studied. We hypothesized that apixaban, compared with warfarin, would be associated with lower risks of progression of chronic kidney disease (CKD) and progression to incident kidney failure in patients with atrial fibrillation (AF).\n\n\nSTUDY DESIGN\nRetrospective cohort study.\n\n\nSETTING & PARTICIPANTS\nMedicare recipients with stages 3, 4, or 5 CKD and incident AF who received a new prescription for apixaban or warfarin between 2013 and 2017.\n\n\nEXPOSURE\nApixaban or warfarin.\n\n\nOUTCOMES\nProgression to incident kidney failure or, separately, to a more advanced stage of CKD.\n\n\nANALYTICAL APPROACH\nMarginal structural cause-specific proportional hazards models with inverse probability weighting to estimate marginal hazard ratios (HRs) for each outcome. HRs compared apixaban to warfarin in intention-to-treat (ITT) and censored-at-drug-switch (CAS) analyses.\n\n\nRESULTS\nA total of 12,816 individuals met inclusion criteria (50.3% apixaban, 49.7% warfarin). After weighting, the mean age of the cohort was 80 ± 7 years; 51% were women, and 88% were White. Approximately 84% had stage 3, 15% stage 4, and 1% stage 5 CKD. In the ITT analysis, apixaban, relative to warfarin, was associated with a HR of developing incident kidney failure of 0.98 (95% confidence interval [CI] 0.79-1.22) and of progression of CKD of 0.90 (95% CI, 0.82-0.99). Corresponding HRs for the CAS analyses were 0.81 (95% CI, 0.56-1.17) and 0.81 (95% CI, 0.70-0.92). Results were similar for a series of subgroup and sensitivity analyses.\n\n\nLIMITATIONS\nCKD was defined based on diagnosis codes from claims; findings may not be generalizable to non-Medicare CKD populations.\n\n\nCONCLUSIONS\nApixaban, compared with warfarin, was associated with lower risk of CKD stage progression, but not with incident kidney failure.