Rates of Adverse Events Lower With Apixaban for A-Fib in Older Adults

TUESDAY, July 20, 2021 (HealthDay News) — For older adults with atrial fibrillation, apixaban is associated with lower rates of adverse events than warfarin across all frailty levels, according to a study published online July 20 in the Annals of Internal Medicine.

Dae Hyun Kim, M.D., M.P.H., Sc.D., from Harvard Medical School in Boston, and colleagues examined outcomes for Medicare beneficiaries with atrial fibrillation receiving direct oral anticoagulants (dabigatran, rivaroxaban, and apixaban) versus warfarin by frailty levels in a propensity score-matched analysis. A composite end point of death, ischemic stroke, or major bleeding was the primary outcome.

The researchers found that the event rate per 1,000 person-years was 63.5 and 65.6 for dabigatran and warfarin initiators, respectively (hazard ratio [95 percent confidence interval], 0.98 [0.92 to 1.05]). The hazard ratios were 0.81 (0.68 to 0.97), 0.98 (0.90 to 1.08), and 1.09 (0.96 to 1.23) for nonfrail, prefrail, and frail individuals, respectively. The event rate per 1,000 person-years was 77.8 and 83.7 for rivaroxaban and warfarin initiators, respectively (hazard ratio, 0.98 [0.94 to 1.02]). The hazard ratios were 0.88 (0.77 to 0.99), 1.04 (0.98 to 1.10), and 0.96 (0.89 to 1.04) for nonfrail, prefrail, and frail individuals, respectively. For apixaban and warfarin initiators, the event rate per 1,000 person-years was 60.1 and 92.3, respectively (hazard ratio, 0.68 [0.65 to 0.72]). The hazard ratios were 0.61 (0.52 to 0.71), 0.66 (0.61 to 0.70), and 0.73 (0.67 to 0.80) for nonfrail, prefrail, and frail individuals, respectively.

“Only apixaban was consistently associated with lower rates of the composite end point of death, ischemic stroke, and major bleeding than warfarin across all frailty levels,” the authors write.

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