Cardiovascular, Bleeding, and Mortality Risks of Dabigatran in Asians With Nonvalvular Atrial Fibrillation

Abstract

Background and purpose: Whether dabigatran is associated with different risks of cardiovascular, bleeding events, and mortality from warfarin in Asian patients with nonvalvular atrial fibrillation remains unclear.

Methods: We used the Taiwan National Health Insurance Research Database to obtain 9940 and 9913 nonvalvular atrial fibrillation patients taking dabigatran and warfarin, respectively, from June 1, 2012, to December 31, 2013, as the dynamic cohort. Inverse probability of treatment weighting using propensity scores was used to balance covariates across 2 study groups. Patients were followed up until the first occurrence of any study outcome or end date of study.

Results: During a median follow-up period of 0.67 years, there were 526 outcomes for dabigatran group. The hazard ratios (95% confidence intervals) comparing dabigatran with warfarin (reference) were as follows: ischemic stroke, 0.62 (0.52-0.73; P<0.0001); myocardial infarction, 0.67 (0.43-1.05; P=0.0803); intracranial hemorrhage, 0.44 (0.32-0.60; P<0.0001); major gastrointestinal bleeding, 0.99 (0.66-1.49; P=0.9658); all hospitalized major bleeding, 0.58 (0.46-0.74; P<0.0001); and all-cause mortality, 0.45 (0.38-0.53; P<0.0001). Dabigatran did not increase the risk of myocardial infarction or major gastrointestinal bleeding in all age groups when compared with warfarin. Total 8772 patients (88%) took a 110-mg dose in dabigatran group. The magnitude of effect for each outcome of 110-mg was comparable with that of 150-mg dose in the subgroup analysis.

Conclusions: In real-world practice, dabigatran was associated with a reduced risk of ischemic stroke, intracranial hemorrhage, all hospitalized major bleeding, and all-cause mortality compared with warfarin in Asian patients with nonvalvular atrial fibrillation. Dabigatran did not increase the risk of major gastrointestinal bleeding or myocardial infarction compared with warfarin.

Keywords: anticoagulant agents; atrial fibrillation; direct thrombin inhibitors; hemorrhage; mortality; warfarin.