Efficacy and Safety of Apixaban Compared with Warfarin for Stroke Prevention in Patients with Atrial Fibrillation from East Asia: A Subanalysis of the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) Trial

Background The perceived risk of serious bleeding is an obstacle to the use of oral anticoagulation in East Asia. The efficacy and safety of apixaban in East Asian patients with atrial fibrillation are unknown. Methods ARISTOTLE included 18,201 patients with nonvalvular atrial fibrillation randomized to apixaban 5 mg twice daily or warfarin. The efficacy and safety of apixaban and warfarin among patients recruited from East Asia (n = 1,993) were compared with those recruited from outside East Asia (n = 16,208). Results Compared with warfarin, apixaban resulted in a consistent reduction in stroke or systemic embolism in East Asian (hazard ratio [HR] 0.74, 95% CI 0.50-1.10) and non-East Asian (HR 0.81, 95% CI 0.66-0.99) patients (interaction P = .70). Consistent benefits of apixaban over warfarin were also seen for major bleeding in East Asian (HR 0.53, 95% CI 0.35-0.80) and non-East Asian (HR 0.72, 95% CI 0.62-0.83) patients (interaction P = .17). There was a greater reduction in major or clinically relevant nonmajor bleeding with apixaban compared with warfarin in East Asian (HR 0.49, 95% CI 0.35-0.67) than in non-East Asian (HR 0.71, 95% CI 0.63-0.79) patients (interaction P = .03). Numerically higher rates of intracranial bleeding were seen in East Asian patients with warfarin but not with apixaban. Conclusions Apixaban resulted in similar reductions in stroke or systemic embolism and major bleeding and greater reductions in major or clinically relevant nonmajor bleeding in patients from East Asia. Warfarin is associated with more intracranial bleeding, particularly in patients from East Asia.