Dabigatran, Rivaroxaban, and Warfarin in the Oldest Adults with Atrial Fibrillation in Taiwan

Abstract

Objectives: To compare the effectiveness and safety of reduced-dose dabigatran, reduced-dose rivaroxaban, and warfarin in individuals aged 85 and older with atrial fibrillation (AF).

Design: Retrospective cohort study.

Setting: Taiwan National Health Insurance claims database, 2011∼2015.

Participants: Individuals with AF aged 85 and older (mean 88.6) with incident use of oral anticoagulants between June 1, 2012 and May 31, 2015 (N=4,722; dabigatran 110 mg, n=1,489; rivaroxaban 15 mg/10 mg, n=1,736; warfarin, n=1,497).

Measurements: Clinical outcomes included all-cause death, cardiovascular death, ischemic stroke, acute myocardial infarction, arterial embolism or thrombosis, intracranial hemorrhage, and gastrointestinal hemorrhage needing transfusion. Propensity score-matched analysis was performed, and the marginal proportional hazards model was used to estimate the relative risk of various clinical outcomes in a matched dabigatran-warfarin cohort (n=1,180 in each group) and a rivaroxaban-warfarin cohort (n=1,207 in each group) RESULTS: Mean follow-up was 6.6 months for the overall population. Dabigatran group participants had lower risks of all-cause death (hazard ratio (HR)=0.59, 95% confidence interval (CI)=0.45-0.77) and cardiovascular death (HR=0.45, 95% CI=0.30-0.68) than warfarin group participants. Rivaroxaban users also had lower risks of all-cause death (HR=0.61, 95% CI=0.47-0.79) and cardiovascular death (HR=0.52, 95% CI=0.35-0.75) than warfarin users. Dabigatran users also had a lower risk of intracranial hemorrhage than warfarin users (HR=0.31, 95% CI=0.10-0.97).

Conclusion: Individuals with AF aged 85 and older who used reduced-dose dabigatran or reduced-dose rivaroxaban had statistically significantly lower all-cause mortality and cardiovascular mortality than those who used warfarin. Reduced-dose dabigatran was also associated with lower risk of intracranial hemorrhage than warfarin.

Keywords: dabigatran; effectiveness; octogenarian; rivaroxaban; safety; warfarin.