Outcomes of Direct Oral Anticoagulants in Atrial Fibrillation Patients Across Different Body Mass Index Categories.

OBJECTIVES This study sought to evaluate direct oral anticoagulant (DOAC) outcomes (vs. warfarin) in patients with atrial fibrillation (AF) across body mass index (BMI) categories, including ≥40 and <18.5 kg/m2. BACKGROUND Clinical trials have not systematically tested the fixed DOAC dosing in underweight and morbidly obese patients. METHODS We retrospectively included consecutive patients with nonvalvular AF with CHA2DS2-VASc (Congestive heart failure, Hypertension, Age ≥75, Diabetes, Stroke/transient ischemic attack/systemic thromboembolism, Vascular disease, Age 65-74, Sex) of ≥1 receiving OACs at our hospital system (2010-2018). Patients were categorized into groups 1 (underweight: BMI of <18.5 kg/m2), 2 (normal/overweight: BMI of 18.5 to <30 kg/m2), 3 (grade 1/2 obesity: BMI of 30 to <40 kg/m2), and 4 (grade 3 obesity: BMI of ≥40 kg/m2). We further classified patients by DOAC versus warfarin use. Outcomes were ischemic stroke, significant bleeding events (i.e., resulting in hospitalization), and mortality. RESULTS We included 36,094 patients with a mean age of 74 ± 11 years and CHA2DS2-VASc of 3.4 ± 1.5. Groups 1 through 4 included 455 (1.3%), 18,339 (50.8%), 13,376 (37.1%), and 3,924 (10.9%) patients, respectively. DOAC use ranged from 49% to 56%. At 3.8 follow-up years, with multivariable Cox regression, DOACs (vs. warfarin) were associated with lower risk of ischemic stroke, bleeding, and mortality across all BMI groups, with hazard ratios (HRs) (95% confidence intervals [CIs]) of 0.73 (0.63 to 0.85), 0.75 (0.64 to 0.87), 0.75 (0.65 to 0.88), and 0.75 (0.64 to 0.87) (p < 0.001 for all) for ischemic stroke; 0.42 (0.19 to 0.92), 0.41 (0.19 to 0.89), 0.45 (0.20 to 1.00), and 0.43 (0.20 to 0.94) (p < 0.05 for all) for bleeding; and 0.90 (0.68 to 1.19; p = 0.5), 0.70 (0.66 to 0.75; p < 0.0001), 0.65 (0.60-0.71; p < 0.0001), and 0.66 (0.56 to 0.77; p < 0.0001) for mortality, in groups 1 to 4, respectively. CONCLUSIONS In patients with nonvalvular AF, DOACs compared to warfarin were associated with better safety and effectiveness across all BMI categories, including underweight and morbidly obese patients.