Gender-specific association between body mass index and all-cause mortality in patients with atrial fibrillation

Background Elevated body mass index (BMI) is related with reduced mortality in various cardiovascular diseases. Hypothesis Gender-specific association between BMI and mortality exists in atrial fibrillation (AF). Methods In this multicenter observational study with a mean follow-up of 1 year, a total of 1991 AF patients were enrolled and divided into two groups based on the gender. The primary endpoint was all-cause mortality while the secondary endpoints were defined as cardiovascular mortality, stroke, and major adverse events during 1-year follow-up. Cox regression was performed to identify the association between BMI and clinical outcomes according to gender. Results Female patients with AF tended to be older (P = .027) and thinner (P < .001) than male patients with AF. They were more likely to have heart failure, hyperthyroidism, and valvular AF (all P < .05), but less likely to have coronary artery disease and prior myocardial infarction (all P < .01). Multivariate analysis revealed that overweight (HR(95%CI): 0.55(0.41-0.75), P < .001) and obese patients (HR(95%CI): 0.56(0.34-0.94), P = .028) were associated with significant lower all-cause mortality compared with normal weight patients for the entire cohort. Similar association between elevated BMI and reduced all-cause mortality were only identified in female patients with AF (overweight vs normal weight: HR(95%CI): 0.43(0.27-0.70); obesity vs normal weight: HR(95%CI): 0.46(0.22-0.97)), but not in male patients with AF. Conclusion This study indicates that overweight and obesity were related with improved survival in patients with AF. The association between elevated BMI and reduced mortality was dependent on gender, which was only significant in female patients, rather than male patients.