Effectiveness and Safety of Direct Oral Anticoagulants and Warfarin, Stratified by Stroke Risk in Patients With Atrial Fibrillation

Abstract

The objective of the study was to examine how the comparative effectiveness and safety of direct oral anticoagulants (DOACs) and warfarin differ across subgroups of patients with atrial fibrillation defined by stroke risk (CHA2DS2-VASc score ≤3, 4 to 5, ≥6). Using Medicare claims data, we identified patients newly diagnosed with atrial fibrillation in 2013 to 2014 who initiated warfarin (n=12,354), apixaban (n=2,358), dabigatran (n=1,415), or rivaroxaban (n=5,139), and categorized them according to their CHA2DS2-VASc score (≤3, 4 to 5, ≥6). Primary outcomes included the combined risk of ischemic stroke, other thromboembolic event and death, and the risk of bleeding. We constructed Cox propor..