Better survival in morbidly obese patients with atrial fibrillation treated with non-vitamin K-dependent oral anticoagulants

Background: The efficacy and safety of non-vitamin K-dependent anticoagulants (NOAC) are not well investigated in the obese population, and fixed dosing could lead to under-anticoagulation. Our objective was to evaluate the effect of obesity on anticoagulation outcomes and survival in non-valvular atrial fibrillation (AF) patients. Methods: We enrolled 755 patients who required anticoagulation for AF from 2015 to 2016. We grouped the patients into four groups. Group 1 (n = 297) included patients with BMI< 40 kg/m2 treated with NOACs, Group 2 (n = 358) included patients on warfarin with BMI< 40 kg/m2, Group 3 (n = 57) had patients on NOACs with BMI≥ 40 kg/m2 and Group 4 (n = 43) included patients on warfarin and BMI≥ 40 kg/m2. Study outcomes were the composite endpoint of stroke, bleeding, and survival. Results: Competing risk regression showed that stroke and bleeding were not affected by obesity or treatment (SHR: 1.09 (95% CI: 0.79-1.51); P = 0.62). Older age was the predictor of stroke/bleeding (HR:1.03 (95% CI:1.01-1.06); P = 0.02). Predictors of mortality were heart failure (HR:2.23 (95% CI:1.25-3.97); P = 0.007), lower creatinine clearance (HR: 0.98 (95% CI:0.97-0.98): P < 0.001), non-obese patients on warfarin (HR:3.51 (95%CI:1.6-7.7): P = 0.002) and obese patients on warfarin (HR: 6.7 (95% CI:2.51-17.92); P < 0.001). Conclusion: NOACs could have a similar risk profile to warfarin in obese and non-obese patients with non-valvular AF but could have better survival. Larger randomized trials are recommended.