0002Anticoagulation in the Extreme Obese: Evaluating Stroke and Bleeding Risk with Warfarin vs. Rivaroxaban in Atrial Fibrillation (AF) and Atrial Flutter

Background Optimal anticoagulation strategies in patients with extreme obesity (BMI ≥ 50 kg/m²) and atrial fibrillation (AF) remain uncertain due to limited trial data and concerns about altered pharmacokinetics. This study compared outcomes between warfarin and rivaroxaban in this population. Methods Using the TriNetX Research Network (111 healthcare organizations), we identified adults with AF or atrial flutter and BMI ≥ 50 kg/m² who received warfarin (n = 12,220) or rivaroxaban (n = 8,260). After 1:1 propensity score matching for demographics, comorbidities, and antiplatelet use, 8,192 patients per cohort were analyzed. Primary outcomes included all-cause mortality, ischemic stroke, venous thromboembolism (VTE), hemorrhagic stroke, and gastrointestinal bleeding over 12 months. Results Matched cohorts were balanced (mean age 60.2 years, 55% female). Warfarin was associated with higher all-cause mortality than rivaroxaban (12.3% vs. 8.4%; risk ratio 1.47, 95% CI 1.34–1.61, p<0.001; hazard ratio 1.46, 95% CI 1.32–1.61, p=0.005). Ischemic stroke risk was more than twofold higher with warfarin (0.5% vs. 0.2%; risk ratio 2.40, 95% CI 1.34–4.31, p=0.002). Rates of VTE, hemorrhagic stroke, and gastrointestinal bleeding did not differ significantly between groups. The absolute risk reduction for mortality with rivaroxaban was 3.9% (number needed to treat = 26). Conclusion In extremely obese patients with AF, rivaroxaban was associated with significantly lower mortality and ischemic stroke without increased bleeding risk. These real-world data support rivaroxaban as a potentially safer and more effective alternative to warfarin in this high-risk population, warranting prospective validation. Is this an encore abstract? No