Clinical question: Is dabigatran superior to warfarin with regards to the risk of intracranial hemorrhage and myocardial infarction in patients with atrial fibrillation?
Background: Several studies – including the RELY trial – have revealed a lower rate of intracranial hemorrhage with dabigatran, compared with warfarin, in patients with atrial fibrillation; however, few of these have been on populations generalizable to clinical practice. Furthermore, there are conflicting data on the association of dabigatran with higher rates of myocardial infarction in patients with atrial fibrillation versus warfarin.
Study design: Retrospective cohort study.
Setting: The (national surveillance system) including 17 collaborating institutions and health care delivery systems.
Synopsis: In 25,289 propensity score–matched pairs of commercially insured patients aged 21 years or older starting dabigatran or warfarin therapy for atrial fibrillation, dabigatran was associated with a lower rate of intracranial hemorrhage (hazard ratio, 0.89; 95% confidence interval, 0.72-1.09), similar rates of ischemic stroke and extracranial hemorrhage, and a potentially higher rate of myocardial infarction (HR, 1.88; 95% CI, 1.22-2.90). However, the association between dabigatran use and myocardial infarction was smaller and not statistically significant in sensitivity analyses. Also, subgroup analyses demonstrated higher rates of gastrointestinal bleeding with dabigatran than did warfarin in patients aged 75 years or older and those with kidney dysfunction.
Although providing further reassuring evidence about bleeding risks – particularly intracranial hemorrhage – associated with dabigatran use, this observational study fails to clarify the association between dabigatran and myocardial infarction.
Bottom line: Dabigatran, compared with warfarin, in adults with atrial fibrillation is associated with a lower risk of intracranial hemorrhage and similar risk of ischemic stroke and extracranial hemorrhage.
Citation: Go AS et al. Outcomes of dabigatran and warfarin for atrial fibrillation in contemporary practice..
Dr. Mehta is assistant professor, division of hospital medicine, University of Virginia.