Comparative safety and effectiveness of direct oral anticoagulants in patients with atrial fibrillation in clinical practice in Scotland.

AIMS: To compare the clinical effectiveness and safety of direct oral anticoagulants (DOACs) in patients with atrial fibrillation (AF) in routine clinical practice.

METHODS: Retrospective cohort study using linked administrative data. The study population (n=14,577) included patients with a diagnosis of AF (confirmed in hospital) who initiated DOAC treatment in Scotland between August 2011 and December 2015. Multivariate Cox proportional hazard models were used to estimate hazard ratios of thromboembolic events, mortality, and bleeding events.

RESULTS: No differences between the DOACs were observed in the risks of stroke, systemic embolism, or cardiovascular death. In contrast, the risk of myocardial infarction was higher among apixaban patients in comparison to rivaroxaban (1.67 [1.02 - 2.71]), and all-cause mortality was higher among rivaroxaban patients in contrast to both apixaban (1.22 [1.01 - 1.47]) and dabigatran (1.55 [1.16 - 2.05]); rivaroxaban patients also had a higher risk of pulmonary embolism than apixaban patients (5.27 [1.79 - 15.53]). The risk of other major bleeds was higher among rivaroxaban patients compared to apixaban (1.50 [1.10 - 2.03]) and dabigatran (1.58 [1.01 - 2.48]); the risks of gastro-intestinal bleeds and overall bleeding were higher among rivaroxaban patients than among apixaban patients (1.48 [1.01 - 2.16] and 1.52[1.21 - 1.92], respectively).

CONCLUSIONS: All DOACs were similarly effective in preventing strokes and systemic embolisms, while patients being treated with rivaroxaban exhibited the highest bleeding risks. Observed differences in the risks of all-cause mortality, myocardial infarction, and pulmonary embolism warrant further research.