Abstract 17617: History of Bleeding and Outcomes with Apixaban versus Warfarin in Patients with Atrial Fibrillation in the ARISTOTLE Trial

Abstract

Background: History of bleeding is important in decisions for anticoagulation. We analyzed outcomes in relation to history of bleeding and randomized treatments in patients with atrial fibrillation (AF) in the ARISTOTLE trial. Methods: The on-treatment safety population included 18,140 patients receiving ≥1 dose of study drug, apixaban 5 mg bd (2.5 mg bd if 2 of the following: age >80 yrs; body weight <60 kg; or creatinine >133 μmol/L) or warfarin aiming for INR 2.0-3.0 (median TTR 66%), for a median of 1.8 yrs. Adjudicated outcomes in relation to randomization and history of bleeding were analyzed using a Cox proportional hazards model. Efficacy endpoints were analyzed in the intention-to-treat population. Results: A history of bleeding was reported in 3033 patients (16.7%), who more often were male (68% vs 64%, p <0.0005); with a history of prior stroke/TIA/systemic embolism (23% vs 19%, p <0.0001); diabetes (27% vs 24%, p=0.0010); higher CHADS2 score (CHADS2 >3: 35% vs 29%), age (mean [SD] 71 [9] vs 69 [10], p <0001) and body weight (86 [21] vs 84 [21], p <0.0001); lower creatinine clearance (77 [33] vs 80 [33], p=0.0007) and mean systolic blood pressure (131 [17] vs 132 [16], p=0.0027). Calcium channel blockers, statins, non-steroidal anti-inflammatory drugs and proton pump inhibitors were used more often in patients with vs without a history of bleeding. Major bleeding was the only outcome event occurring more frequently in patients with vs without a history of bleeding, HR 1.7 (95% CI 1.4-2.3) with apixaban and 1.5 (1.2-1.0) with warfarin. Primary efficacy and safety outcomes in relation to randomization, see Table. Conclusions: In patients with AF, a history of bleeding was associated with several risk factors for stroke and bleeding and, accordingly, a higher bleeding risk during anticoagulation. Benefits with apixaban vs warfarin as to stroke, mortality and major bleeding, are however consistent irrespective of bleeding history.