Obesity paradox in atrial fibrillation patients on oral anticoagulation therapy: a Korean nationwide cohort study

Abstract

Abstract Background The obesity paradox is a phenomenon that has been observed in specific pathological conditions, wherein individuals who are overweight or obese exhibit a survival advantage over those with a normal weight. This phenomenon has also been noted in patients diagnosed with atrial fibrillation (AF), although the impact of body mass index (BMI) on clinical outcomes in AF patients undergoing oral anticoagulant (OAC) therapy remains uncertain. Purpose The aim of this study was to investigate the potential relationship between obesity and cardiovascular outcomes in patients diagnosed with AF who were receiving OAC. Methods We utilized administrative claims data from the Korean National Health Insurance Service and the combined health check-up database of the National Health Insurance Corporation to conduct a retrospective national cohort study spanning from 2013 to 2020. The patients newly prescribed OAC for AF were included, between January 2015 and December 2019. We followed up with patients from their index date until each outcome event or the end of the study period. BMI was categorized into 5 groups based on the World Health Organization's recommended criteria for Asian populations. The predefined clinical outcomes included thromboembolism, major bleeding, all-cause death, and the composite outcome. Results A total of 35,333 patients were included in the study. The mean age was 69 ± 10 years, and 37.1% were female. During a median follow-up of 2.0 years (IQR, 0.4–3.3), there were 11,634 thromboembolic events, 1,521 major bleeding events, and 2,586 deaths. The adjusted hazard ratio (HR) for thromboembolism, major bleeding, all-cause death, and a composite outcome were lower in obese II group (HR 0.79, 95% CI 0.73–0.86; HR 0.99, 95% CI 0.79–1.24; HR 0.75, 95% CI 0.62–0.91; HR 0.81, 95% CI 0.75–0.88) compared to the normal range BMI group. Conclusions In AF patients undergoing OAC therapy, individuals classified as obese exhibited a reduced risk of thromboembolism, major bleeding, all-cause mortality, and composite outcome compared to patients with normal weight.Adjusted hazard ratio of outcomes by BMI