Abstract 159: Evaluation of Clinical Outcomes among Nonvalvular Atrial Fibrillation Patients Treated With Warfarin or Rivaroxaban Stratified by Presence or Absence of CKD in a Claims Database

Abstract

Introduction: Renal functional impairment is linked to an increased risk of thromboembolic and bleeding events in patients with nonvalvular atrial fibrillation (NVAF) treated with warfarin and rivaroxaban. Anticoagulants such as warfarin and rivaroxaban are often recommended to reduce the risk of stroke in NVAF patients. The purpose of this study was to evaluate and compare thromboembolic and bleeding event rates for warfarin and rivaroxaban patients stratified by presence of chronic kidney disease (CKD). Methods: Claims from the IMS Health Real-World Data Adjudicated Claims database from 05/2011-6/2015 were analyzed. Adult patients with NVAF who had ≥6 months of baseline data prior to the first dispensing of warfarin or rivaroxaban after 11/2011 were included. Patients were followed until the end of index therapy or end of data availability/insurance coverage. Outcomes were stratified by presence of CKD for ischemic stroke, major bleeding, and a composite measure of thromboembolic events (ischemic stroke, myocardial infarction (MI) or venous thromboembolism (VTE)) and analyzed using hazard ratios (HRs). Adjustments for confounding were made with inverse probability of treatment weights (IPTW). Results: The analysis included 39,872 rivaroxaban (9.0% [3,572 of 39,872] with CKD) and 48,637 warfarin patients (16.9% [8,230 of 48,637] with CKD). As expected, thromboembolic and bleeding events were more common in patients with CKD than those without CKD. Rivaroxaban patients had significantly lower risk of ischemic stroke, both in the overall population (HR = 0.79 [0.68-0.90], p=0.0008) and for those with CKD (HR = 0.55 [0.40-0.77], p=0.0004). A composite of thromboembolic events were lower with rivaroxaban irrespective of CKD. Major bleeding rates were comparable across all groups. Table 1 reports incidence rates and HRs stratified by presence of CKD. Conclusions: This study suggests that, in an adult population with NVAF, rivaroxaban-treated patients had fewer ischemic strokes across all patients, including patients with renal impairment. Rivaroxaban-treated patients also had significantly better outcomes for the composite (VTE, MI, or stroke) measure across all groups. Bleeding rates were comparable across all groups.