Thromboembolic and Major Bleeding Events With Rivaroxaban Versus Warfarin Use in a Real-World Setting

Background: Although randomized trials demonstrate the noninferiority of rivaroxaban compared with warfarin in the context of nonvalvular atrial fibrillation (AF), little is known about how these drugs compare in practice. Objective: To assess the relative effectiveness and safety of rivaroxaban versus warfarin in a large health system and to evaluate this association by time in therapeutic range (TTR). Methods: We conducted a retrospective cohort study with propensity matching in the Cleveland Clinic Health System. The study included patients initiated on warfarin or rivaroxaban for thromboembolic prevention in nonvalvular AF between January 2012 and July 2016. The main outcomes were thromboembolic events and major bleeds. Analyses were stratified by warfarin patients’ TTR. Results: The cohort consisted of 472 propensity-matched pairs. The mean age was 73.6 years (SD = 11.7), and the mean CHADS₂ score was 1.8. The median TTR for warfarin patients was 64%. In the propensity-matched analysis, there was no significant difference in thromboembolic or major bleeding events between groups. Among warfarin patients with a TTR <64% and their matched rivaroxaban pairs, there was also no significant difference in thromboembolic or major bleeding events. Conclusions: Under real-world conditions, warfarin and rivaroxaban were associated with similar safety and effectiveness, even among those with suboptimal therapeutic control. Individualized decision making, taking into account the nontherapeutic tradeoffs associated with these medications (eg, monitoring, half-life, cost) is warranted.