Comparative Effectiveness and Safety of Rivaroxaban and Warfarin Among Nonvalvular Atrial Fibrillation (NVAF) Patients with Obesity and Polypharmacy in the United States (US)

INTRODUCTION: Current evidence indicates that rivaroxaban may be a safe and effective alternative to warfarin among patients with nonvalvular atrial fibrillation (NVAF) and obesity. However, evidence regarding the impact of polypharmacy is limited in this population. The present study evaluated the effectiveness and safety of rivaroxaban versus warfarin among NVAF patients with obesity and polypharmacy in the US. METHODS: De-identified health insurance claims data from the IQVIA PharMetrics(®) Plus data (01/2010–09/2019) were used to identify NVAF patients with obesity (BMI ≥ 30 kg/m(2)) and polypharmacy (≥ 5 medications) initiated on rivaroxaban or warfarin. Inverse probability of treatment weighting (IPTW) was used to adjust for imbalances between groups. Study outcomes were evaluated up to 36 months post-treatment initiation and included the composite of stroke or systemic embolism (stroke/SE) and major bleeding. Subgroup analyses were conducted stratified by polypharmacy category (5–9 or ≥ 10 medications). Outcomes were assessed using Cox proportional hazards regression models with hazard ratios (HR) and 95% confidence intervals (CIs). RESULTS: A total of 7000 and 3920 NVAF patients with obesity and polypharmacy were initiated on rivaroxaban and warfarin, respectively. At 36 months of follow-up, rivaroxaban was associated with a 29% lower risk of stroke/SE relative to warfarin (HR 0.71, 95% CI 0.57, 0.90). Major bleeding risk was not significantly different among rivaroxaban- compared to warfarin-treated patients (HR 0.85, 95% CI 0.70, 1.03). Subgroup analyses yielded results that were largely consistent with the overall polypharmacy analysis. CONCLUSIONS: These results suggest that rivaroxaban is an effective and safe treatment option among NVAF patients with obesity and polypharmacy in a commercially-insured US population. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12325-021-01746-2.