A nationwide registry study to compare bleeding rates in patients with atrial fibrillation being prescribed oral anticoagulants

Abstract

Aims We aimed to evaluate bleeding risk in clinical practice in patients with atrial fibrillation (AF) being prescribed dabigatran, rivaroxaban, or apixaban compared with warfarin. Methods Using nationwide registries (Norwegian Patient Registry and Norwegian Prescription Database), we identified AF patients with a first prescription of oral anticoagulants between January 2013 and June 2015. Patients were followed until discontinuation or switching of oral anticoagulants, death, or end of follow-up. The primary endpoint was major or clinically relevant non-major (CRNM) bleeding. Results In total 32 675 AF patients were identified (58% men, median age 74 years): 11 427 patients used warfarin, 7925 dabigatran, 6817 rivaroxaban, and 6506 apixaban. After a median follow-up of 173 days (25th, 75th percentile 84, 340), 2081 (6.37%) patients experienced a first major or CRNM bleeding. Using a Cox proportional hazard model adjusting for baseline characteristics, use of apixaban [hazard ratio (HR) 0.70, 95% confidence interval (CI) 0.61- 0.80, P<0.001] and dabigatran (HR 0.74, 95% CI 0.66-0.84, P<0.001) were associated with a lower risk of major or CRNM bleeding compared with warfarin whereas use of rivaroxaban was not (HR: 1.05, 95% CI 0.94-1.17, P=0.400). Use of dabigatran and rivaroxaban were associated with higher risk of gastrointestinal bleeding, whereas use of apixaban and dabigatran were associated with lower risk of intracranial bleeding, compared with warfarin. Conclusion In this nationwide cohort study in AF patients, apixaban and dabigatran were associated with a lower risk of major or CRNM bleeding compared with warfarin. The risk of gastrointestinal bleeding was higher with rivaroxaban and dabigatran compared with warfarin.