Association between Body Mass Index and Clinical Outcomes in Patients with Non-valvular Atrial Fibrillation Receiving Direct Oral Anticoagulants: A New Piece of Evidence on the Obesity Paradox from China

Purpose We conducted a multicenter real-world study in China to assess the association between body mass index (BMI) and clinical outcomes in patients with atrial fibrillation (AF) taking direct oral anticoagulants (DOACs). Method This is a retrospective multicenter cohort study conducted in 15 centers in China. We collected demographic information through the hospital information system and obtained clinical events through follow-up visits to patients or relatives. Clinical outcomes include major, minor, total bleeding, thromboembolism, and all-cause death. Result A total of 6164 patients with non-valvular AF (NVAF) were included in this study. The incidence of major bleeding in patients with NVAF differed significantly by BMI category (P < 0.001), with 5.2% in the underweight group, 2.6% in the normal group, 1.4% in the overweight group, 1.1% in the obese I group, and 1.3% in the obese II group. There was no significant difference in minor, total bleeding, and thrombosis in the five groups (P = 0.493; P = 0.172; P = 0.663). All-cause death was significantly different among the five groups (P < 0.001), with 8.9% in the underweight group, 6.3% in the normal group, 4.8% in the overweight group, 2.2% in the obese I group, and 0.4% in the obese II group. High BMI was negatively associated with major bleeding (OR = 0.353, 95% CI 0.205-0.608), total bleeding (OR = 0.664, 95% CI 0.445-0.991), and all-cause death (OR = 0.370, 95% CI 0.260-0.527). Conclusion In patients with NVAF treated with DOACs, higher BMI was associated with lower major bleeding and better survival. BMI was a negative correlate of total bleeding, but not minor bleeding and thrombosis.