Gender and racial differences in outcomes among patients with NVAF treated with oral anticoagulants: a real-world evaluation of Medicare beneficiaries
Authors: Atreja N , Kohli M , Hines D M , Jiang J , Hagan M , Aweh G , Adams S , Cheng D 
Published: October 2024

Abstract

Introduction
Anticoagulation therapies are essential component of disease management for patients with atrial fibrillation (AF). Direct-acting oral anticoagulants (DOACs), such as apixaban, rivaroxaban, and dabigatran have shown greater benefit in reducing stroke/systemic embolism (SE) and bleeding risk compared to warfarin. However, few studies have assessed whether the beneficial effects of DOACs are consistent across gender and race.

Purpose
To assess the association between apixaban use and the risk of stroke/SE and major bleeding (MB) compared to warfarin, rivaroxaban, and dabigatran; and to determine whether the associations differ by gender and race.

Methods
Adult patients with AF diagnosis who initiated warfarin or a DOAC between January 1, 2013 and December 31, 2019 were identified using Medicare claims databases. Patients were classified into warfarin, apixaban, dabigatran, or rivaroxaban cohorts based on index prescription. Inverse Probability Treatment Weighting Cox proportional hazard models were used to assess the association between DOAC therapy initiation and risk of stroke/SE and MB, overall and among gender and race.

Results
Among a total of 1,079,540 included patients, 486,257 (45.04%) were in the apixaban cohort, 46,920 (4.35%) in the dabigatran cohort, 267,991 (24.82%) in the rivaroxaban cohort, and 278,372 (25.79%) in the warfarin cohort. Overall, the risks of stroke/SE and MB were lower for apixaban when compared with warfarin (stroke/SE: HR: 0.69 [95% confidence interval (CI): 0.65-0.74], MB: 0.59 [95% CI: 0.57-0.60]), rivaroxaban (stroke/SE: 0.88 [95% CI: 0.84-0.92], MB: 0.60 [95% CI: 0.58-0.61]) and dabigatran(stroke/SE: 0.88 [95% CI: 0.80-0.95], MB: 0.76 [95% CI: 0.72-0.80]). Among 140,587 females, the risk was lower for apixaban as compared with warfarin (stroke/SE: 0.72 [95% CI: 0.67-0.78], MB: 0.60 [95% CI: 0.58-0.62]) and rivaroxaban (stroke/SE: 0.88 [95% CI: 0.83-0.93], MB: 0.59 [95% CI: 0.57-0.61]), but similar risk of stroke/SE was noted for apixaban compared to dabigatran (stroke/SE: 0.98 [95% CI: 0.86-1.11]). Among 137,785 males, the risk of stroke/SE and MB were lower for apixaban compared with warfarin, rivaroxaban, and dabigatran. Among 16,288 Black patients, the risk was lower for apixaban as compared with warfarin (stroke/SE: 0.72 [95% CI: 0.63-0.83] MB: 0.59 [95% CI: 0.54-0.65]), also lower risk of MB was noted for apixaban as compared with rivaroxaban (MB: 0.56 [95% CI: 0.5-0.62]), but a similar risk of stroke/SE was noted compared to rivaroxaban and dabigatran, and similar risk of MB was noted compared to dabigatran. Among 247,642 White patients, the risk of stroke/SE and MB were lower for apixaban compared with warfarin, rivaroxaban, and dabigatran. All the results along with comparisons are displayed in the accompanying figures.

Conclusion
Apixaban demonstrated lower risk of stroke/SE and major bleeding when compared to warfarin, rivaroxaban, and dabigatran across most race and gender subgroups.Figure 1_Risk of stroke/SEFigure 2_Risk of Major Bleeding