Apixaban bests other DOACs in reducing adverse events among frail AF patients

Treatment with apixaban leads to reduced rates of adverse events across all frailty levels among older adults with atrial fibrillation (AF), reports a study. In contrast, dabigatran and rivaroxaban help lower event rates only among nonfrail patients.

The authors carried out a 1:1 propensity score–matched analysis of Medicare data, from 2010 to 2017, to examine the outcomes of direct oral anticoagulants (DOACs) compared to warfarin by frailty levels. They enrolled Medicare beneficiaries with AF who initiated use of dabigatran, rivaroxaban, apixaban, or warfarin. Outcome measured was the composite of death, ischaemic stroke, or major bleeding frailty levels, defined by a claims-based frailty index.

In the dabigatran–warfarin cohort (n=158,730), the event rate per 1,000 person-years over a median follow-up of 72 days was 63.5 for dabigatran initiators and 65.6 for warfarin initiators (hazard ratio [HR], 0.98, 95 percent confidence interval [CI], 0.92–1.05; rate difference [RD], –2.2, 95 percent CI, –6.5 to 2.1). Across frailty levels, HR was 0.81 (95 percent CI, 0.68–0.97) for nonfrail, 0.98 (95 percent CI, 0.90–1.08) for prefrail, and 1.09 (95 percent CI, 0.96–1.23) for frail persons.

In the rivaroxaban–warfarin cohort (n=275,944), the event rate per 1,000 person-years over a median follow-up of 82 days was 77.8 for rivaroxaban initiators and 83.7 for warfarin initiators (HR, 0.98, 95 percent CI, 0.94–1.02; RD, –5.9, 95 percent CI, –9.4 to –2.4). For nonfrail, prefrail, and frail persons, the respective HRs were 0.88 (95 percent CI, 0.77–0.99), 1.04 (95 percent CI, 0.98–1.10), and 0.96 (95 percent CI, 0.89–1.04).

The event rate per 1,000 person-years in the apixaban–warfarin cohort (n=218,738) was 60.1 for apixaban initiators and 92.3 for warfarin initiators during a median follow-up of 84 days (HR, 0.68, 95 percent CI, 0.65–0.72; RD, –32.2, 95 percent CI, –36.1 to –28.3). Across frailty levels, HRs were 0.61 (95 percent CI, 0.52–0.71), 0.66 (95 percent CI, 0.61–0.70), and 0.73 (95 percent CI, 0.67–0.80) for nonfrail, prefrail, and frail persons, respectively.

This study was limited by residual confounding and lack of clinical frailty assessment.