Sex Differences in Dabigatran Use, Safety, And Effectiveness In a Population-Based Cohort of Patients With Atrial Fibrillation.

BACKGROUND Sex differences were observed with regard to warfarin treatment in patients with atrial fibrillation, with women having a higher risk of stroke compared with men. We aimed to compare sex differences in use, safety, and effectiveness of dabigatran. METHODS AND RESULTS We conducted a population-based cohort study of patients with atrial fibrillation using administrative data in Quebec, Canada, 1999 to 2013. Men and women who filled a prescription for dabigatran (110 and 150 mg bid) were compared with matched warfarin users with respect to their rates of stroke, bleeding, and myocardial infarction events, using propensity score analysis. The cohort comprised 31 786 women (50.4%) and 31 324 men (49.6%). Women had a higher baseline stroke risk and lower baseline bleeding risk compared with men. Women filled more prescriptions for the lower dabigatran dose compared with men (adjusted OR, 1.35; 95% confidence interval, 1.24-1.48). In multivariable analyses adjusted for propensity scores, dabigatran use was associated with a lower risk of bleeding compared with warfarin in men (P for interaction=0.008). Dabigatran was associated with a trend toward lower risk of stroke in women treated with the 150-mg dose (HR, 0.79; 95% confidence interval, 0.56-1.04), but was not associated with a difference in the risk of myocardial infarction compared with warfarin in either sex. CONCLUSIONS In real-life practice, women are more frequently treated with low-dose dabigatran, yet a trend toward lower stroke rates in women taking high-dose dabigatran was observed. Men benefit from lower bleeding rates with dabigatran compared with warfarin.