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

ObjectivesTo compare the effectiveness and safety of reduced-dose dabigatran, reduced-dose rivaroxaban, and warfarin in individuals aged 85 and older with atrial fibrillation (AF). DesignRetrospective cohort study. SettingTaiwan National Health Insurance claims database, 2011 approximate to 2015. ParticipantsIndividuals 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). MeasurementsClinical 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) ResultsMean 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). ConclusionIndividuals 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.