Abstract 17246: Risk Factors for Major Bleeding Events in Rivaroxaban Users With Atrial Fibrillation: A Nested Case-control Study

Abstract

Introduction: Rivaroxaban is a novel oral anticoagulant indicated to reduce the risk of stroke and systemic embolism in patients with non-valvular atrial fibrillation (NVAF). Anticoagulation therapies carry a risk of major bleeding (MB), for which patient characteristics may play a role. Methods: Using data obtained from the Department of Defense (DoD), we examined risk factors for MB within a cohort of rivaroxaban-treated patients with NVAF using a nested case-control design. Cases with MB were selected by a validated claims-based algorithm that approximates the definition of MB used in clinical trials. Incidence density sampling was used to identify 5 controls without MB for each case. Controls had the same year of entry into the cohort and were at risk for a MB event at the time of each matched case’s event (index date). Potential risk factors for MB included demographic characteristics and comorbidities from the 12 months prior to the index date. Odds ratios (OR) and 95% confidence intervals (CI) were calculated from multivariable conditional logistic regression models to identify risk factors for bleeding. Results: Among 542 MB cases and 2,710 controls, MB cases were older and had more comorbidities (Table 1). Based on the multivariable modeling, increased age, anemia, prior gastrointestinal bleeding, heart failure, and vascular disease were identified as the strongest risk factors for MB (p<0.0001 for all). Conclusions: Several risk factors for MB were identified, although some findings may be affected by unmeasured confounding effects. These risk factors may assist in the development of clinical management strategies.