Comparative Effectiveness of Dabigatran versus Warfarin in Patients With Non-Valvular Atrial Fibrillation

• Type of Material: Article
• Authors: Lindsay GS Bengtson, Optum; Pamela L. Lutsey, University of Minnesota; Lin Y. Chen, University of Minnesota; Richard F. MacLehose, University of Minnesota; Alvaro Alonso, Emory University
• Language: English
• Date: 2013-11-26
• Publisher: American Heart Association
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2016 Japanese College of Cardiology
• Final Published Version (URL): http://dx.doi.org/10.1016/j.jjcc.2016.08.010
• Title of Journal or Parent Work: Circulation
• ISSN: 0009-7322
• Volume: 128
• Issue: 22
• Start Page: 868
• End Page: 876
• Grant/Funding Information: Grant R01-HL122200 from the National Heart, Lung and Blood Institute, grant 16EIA2640001 from the American Heart Association, the National Center for Advancing Translational Sciences of the National Institutes of Health Award Number UL1TR000114, and a Small Grant from the University of Minnesota Academic Health Center.
• Keywords: Warfarin; Effectiveness; Cardiac & Cardiovascular Systems; Life Sciences & Biomedicine; Atrial fibrillation; Science & Technology; Dabigatran; Peripheral Vascular Disease; Stroke; Cardiovascular System & Cardiology
• Research Categories: Health Sciences, Epidemiology; Health Sciences, Public Health

Abstract

Background Effectiveness data on novel oral anticoagulants (NOACs) versus warfarin for stroke prevention in non-valvular atrial fibrillation (NVAF) by prior warfarin use are limited. Methods We used data from the US MarketScan databases from 2009 to 2012. NVAF patients initiating dabigatran or rivaroxaban were matched with up to 5 warfarin users. Propensity score-adjusted Cox regression was used to calculate hazard ratios (HR) and 95% confidence intervals (95% CI) for relevant endpoints in NOACs versus warfarin users. Separate analyses were conducted to compare anticoagulant-naïve users of NOACs and those switching from warfarin. Results Among 32,918 dabigatran, 3301 rivaroxaban, and 109,447 warfarin users with NVAF, 225 intracranial bleeds, 1035 ischemic strokes, 958 myocardial infarctions, and 1842 gastrointestinal bleeds were identified. Compared to warfarin users, patients initiating NOACs had similar ischemic stroke rates and lower intracranial bleeding rates, while the gastrointestinal bleeding rate was higher in dabigatran users than warfarin users. Associations of dabigatran with ischemic stroke risk differed between anticoagulant-naïve initiators and patients switching from warfarin; dabigatran was associated with lower ischemic stroke rates in naïve users (HR 0.65, 95% CI 0.52–0.82) but not in switchers (HR 1.20, 95% CI 0.95–1.51), compared to warfarin. Risk of stroke and bleeding was not different between rivaroxaban and warfarin users. Conclusions Real-world effectiveness of NOACs (compared to warfarin) for diverse outcomes was comparable to efficacy reported in published clinical trials. However, harms and benefits of switching from warfarin to dabigatran need to be evaluated.