Risks of Dabigatran in Asians With Atrial Fibrillation
Is dabigatran associated with different risks of cardiovascular, bleeding events, and mortality from warfarin in Asian patients with nonvalvular atrial fibrillation (AF)?
Using the Taiwan National Health Insurance Research Database, patients taking dabigatran (9,940) or warfarin (9,913) between June 1, 2012 and December 31, 2013 were analyzed. Propensity score weighting was used to balance measured covariates between the two groups. Patients were followed until the first occurrence of any study outcome or end of the study period. Outcomes measured included ischemic stroke, acute myocardial (MI), intracranial hemorrhage, major gastrointestinal (GI) bleeding, all major bleeding events, and all-cause mortality.
There were 526 outcomes in the dabigatran group over a median follow-up of 0.67 years. As compared to the warfarin group, adjusted rates of ischemic stroke (hazard ratio [HR], 0.62; 95% confidence interval [CI], 0.52-0.73), intracranial hemorrhage (HR, 0.44; 95% CI, 0.32-0.60), all major bleeding (HR, 0.58; 95% CI, 0.46-0.74), and all-cause mortality (HR, 0.45; 95% CI, 0.38-0.53) were reduced in the dabigatran-treated group. Rates of MI (HR, 0.67; 95% CI, 0.43-1.05) and major GI bleeding (HR, 0.99; 95% CI, 0.66-1.49) were similar between the two treatment groups. The majority of dabigatran patients (88%) were prescribed the 110 mg dose of dabigatran, but the magnitude of effect for each outcome was similar between the 110 mg and 150 mg doses.
The authors concluded that in real-world practice, dabigatran was associated with reduced risk of ischemic stroke, intracranial hemorrhage, major bleeding, and all-cause mortality as compared to warfarin in Asian patients with nonvalvular AF. They also concluded that use of dabigatran was not associated with an increased risk of major GI bleeding or MI as compared to warfarin.
This large real-world analysis provides some reassuring findings that support the randomized RE-LY trial comparing dabigatran to warfarin for stroke prevention in nonvalvular AF. Specifically, rates of intracranial hemorrhage were reduced (as was seen in all trials of direct oral anticoagulants) as well as rates of ischemic stroke (seen only in the RE-LY trial). Reassuringly, this study demonstrated no increased risk of MI or GI bleeding, both of which were concerns from early analyses of the RE-LY trial. However, clinicians should note that this study primarily analyzed patients treated with the 110 mg dose of dabigatran, a dose not available in the United States.
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