Clinical outcomes in patients with atrial fibrillation receiving amiodarone on NOACs vs. warfarin

Abstract

Purpose: Amiodarone is a potent inhibitor of the CYP450:3A4 and inhibitor of the P-glycoprotein, both of which metabolize new oral anticoagulants (NOACs). Patients who are on NOACs and are concomitantly treated with amiodarone may have a higher risk of major bleeding according to recent retrospective trials. Whether this increased risk outweighs the benefits of NOACs compared to warfarin is unknown. We aimed to compare clinical outcomes between NOACs and warfarin in patients with atrial fibrillation (AF) being treated with amiodarone. Methods: We performed a systematic review of MEDLINE, Cochrane, and Embase for randomized controlled trials that compared NOACs to warfarin for prophylaxis of ischemic stroke/thromboembolic events (TEs) in patients with AF and reported outcomes on TE, major bleeding, and intracranial bleeding (ICB). Risk ratio (RR) and 95% confidence intervals were measured using the Mantel-Haenszel method. Fixed effects model was used, and if heterogeneity (I2) was > 25%, effects were analyzed using a random model. Results: A total of four studies comparing NOACs to warfarin were included in the analysis. The total number of patients on amiodarone was 6197. Mean follow up was 23 ± 5 months. No statistically significant difference for TE prevention (RR, 0.73; 95% CI 0.50–1.07), major bleeding (RR, 1.02; 95% CI 0.68–1.53), or ICB outcomes (RR, 0.58; 95% CI 0.22–1.51) between patients on NOACs + amiodarone when compared to patients on warfarin + amiodarone. Conclusion: Among patients with AF taking amiodarone, there is no increased risk of stroke, major bleeding, or ICB with NOACs compared to warfarin.