Comparative Outcomes Between Direct Oral Anticoagulants, Warfarin, and Antiplatelet Monotherapy Among Chinese Patients with Atrial Fibrillation: A Population-Based Cohort Study

Introduction Outcomes associated with suboptimal use of antithrombotic treatments (antiplatelets, warfarin, direct oral anticoagulants [DOACs]) are unclear in Chinese patients with atrial fibrillation (AF). Objectives Our objective was to assess the prescription patterns, quality, effectiveness, and safety of antithrombotic treatments. Methods This was a population-based cohort study using electronic health records in Hong Kong. Patients newly diagnosed with AF during 2010-2016 were followed up until 2017. Patients at high stroke risk (CHA2DS2-VASc score >= 2) and receiving antithrombotic treatments were matched using propensity scoring. We used Cox proportional hazards regression to compare the risks of ischemic stroke, intracranial hemorrhage (ICH), gastrointestinal bleeding (GIB), and all-cause mortality between groups. Results Of the 52,178 high-risk patients with AF, 27,614 (52.9%) received antithrombotic treatment and were included in the analyses. Between 2010 and 2016, prescribing of antiplatelets and warfarin declined and that of DOACs increased dramatically (from 1 to 32%). Two-thirds of warfarin users experienced poor anticoagulation control. Warfarin and DOACs were associated with lower risks of ischemic stroke (warfarin, hazard ratio [HR] 0.51 [95% confidence interval (CI) 0.36-0.71]; DOACs, HR 0.69 [95% CI 0.51-0.94]) and all-cause mortality (warfarin, HR 0.47 [95% CI 0.39-0.57]; DOACs, HR 0.45 [95% CI 0.37-0.55]) than were antiplatelets. DOACs were associated with a lower risk of ICH than was warfarin (HR 0.53 [95% CI 0.34-0.83]). GIB risks were similar among all groups. Conclusion Antiplatelet prescribing and suboptimal warfarin management remain common in Chinese patients with AF at high risk of stroke. DOAC use may be associated with a lower risk of ischemic stroke and all-cause mortality when compared with antiplatelets and with a lower risk of ICH when compared with warfarin.