LAUSR

Background Apixaban and rivaroxaban are the most commonly prescribed direct oral anticoagulants for adults with atrial fibrillation, but head-to-head data comparing their safety and effectiveness are lacking. Objective To compare the safety and effectiveness of apixaban versus rivaroxaban for patients with nonvalvular atrial fibrillation. Design New-user, active-comparator, retrospective cohort study. Setting A U.S. nationwide commercial health care claims database from 28 December 2012 to 1 January 2019. Patients Adults newly prescribed apixaban (n = 59 172) or rivaroxaban (n = 40 706). Measurements The primary effectiveness outcome was a composite of ischemic stroke or systemic embolism. The primary safety outcome was a composite of intracranial hemorrhage or gastrointestinal bleeding. Results 39 351 patients newly prescribed apixaban were propensity score matched to 39 351 patients newly prescribed rivaroxaban. Mean age was 69 years, 40% of patients were women, and mean follow-up was 288 days for new apixaban users and 291 days for new rivaroxaban users. The incidence rate of ischemic stroke or systemic embolism was 6.6 per 1000 person-years for adults prescribed apixaban compared with 8.0 per 1000 person-years for those prescribed rivaroxaban (hazard ratio [HR], 0.82 [95% CI, 0.68 to 0.98]; rate difference, 1.4 fewer events per 1000 person-years [CI, 0.0 to 2.7]). Adults prescribed apixaban also had a lower rate of gastrointestinal bleeding or intracranial hemorrhage (12.9 per 1000 person-years) compared with those prescribed rivaroxaban (21.9 per 1000 person-years), corresponding to an HR of 0.58 (CI, 0.52 to 0.66) and a rate difference of 9.0 fewer events per 1000 person-years (CI, 6.9 to 11.1). Limitation Unmeasured confounding, incomplete laboratory data. Conclusion In routine care, adults with atrial fibrillation prescribed apixaban had a lower rate of both ischemic stroke or systemic embolism and bleeding compared with those prescribed rivaroxaban. Primary Funding Source Division of Pharmacoepidemiology and Pharmacoeconomics, Brigham and Women's Hospital.