Thromboembolic and bleeding risk in obese patients with atrial fibrillation according to different anticoagulation strategies

Background. Data on the relationship between body mass index (BMI), thromboembolic events (TEE) and bleeding in patients with atrial fibrillation (AF) are controversial, and further evidence on the risk of such events in obese patients with AF receiving different anticoagulant therapies (OAC) is needed. Methods and Results. We divided a total of 9,330 participants from the prospective PREFER in AF and PREFER in AF PROLONGATION registries into BMI quartiles at baseline. Outcome measures were TEE and major bleeding complications at the 1-year follow-up. Without OAC, there was a ≥6-fold increase of TEE in the 4th vs other BMI quartiles (P=0.019). OAC equalized the rates of TEE across different BMI strata. The occurrence of major bleeding was highest in patients with BMI in the 1st as well as in the 4th BMI quartile [OR 1.69, 95% CI 1.03-2.78, P=0.039 and OR 1.86, 95% CI 1.13-3.04, P=0.014 vs those in the 3rd quartile, respectively]. At propensity score-adjusted analysis, the incidence of TEE and major bleeding in obese patients receiving non-vitamin K antagonist oral anticoagulants (NOACs) or vitamin K-antagonist anticoagulants (VKAs) was similar (P≥0.34). Conclusions. Our real-world data suggest no obesity paradox for TEE in patients with AF. Obese patients are at higher risk of TEE, and here OAC dramatically reduces the risk of events. We here found a comparable clinical outcome with NOACs and VKAs in obese patients. Low body weight and obesity were also associated with bleeding, and therefore OAC with the best safety profile should be considered in this setting.