Risk of major bleeding and thromboembolism in Asian patients with nonvalvular atrial fibrillation using direct oral anticoagulants versus warfarin.

Background Bleeding and thromboembolism prevention is important in patients with nonvalvular atrial fibrillation receiving anticoagulants, including direct oral anticoagulants and warfarin. Asians have higher risks of bleeding complications when taking anticoagulants. However, evidence that considers laboratory parameters is lacking. Objective We aimed to compare the safety and effectiveness between direct oral anticoagulants and warfarin in Asian patients with nonvalvular atrial fibrillation. Setting Retrospective design using hospital-based data. Method This propensity score-matched cohort study included data extracted from the electronic medical records of the En Chu Kong Hospital Research Database. Main outcome measure Outcome measures were major bleeding and thromboembolism. Cox proportional hazard models were applied for evaluating hazard ratios with 95% confidence intervals. Results Among 1075 patients with nonvalvular atrial fibrillation, 687 and 388 were administered direct oral anticoagulants and warfarin, respectively. After propensity score matching, 264 patient pairs were selected. Compared with warfarin use, direct oral anticoagulant use was associated with similar risks for major bleeding and thromboembolism; however, the latter was associated with increased gastrointestinal bleeding risks (adjusted hazard ratio 3.59; 95% confidence interval, 1.31-11.39). Notably, an approximately 10 fold increased risk of gastrointestinal bleeding was observed in 0-6 month direct oral anticoagulant users (adjusted hazard ratio 10.13, 95% confidence interval 1.27-80.89). Conclusion Direct oral anticoagulant use was not associated with major bleeding and thromboembolism occurrence in Asian patients with nonvalvular atrial fibrillation. However, direct oral anticoagulant use was associated with increased gastrointestinal bleeding risks, especially when used within 0-6 months of direct oral anticoagulant use.