Association between body mass index and mortality in atrial fibrillation patients with and without diabetes mellitus: Insights from a multicenter registry study in China

Abstract

Background and aims: The aim of this study was to evaluate the association between body mass index (BMI) and mortality in atrial fibrillation (AF) patients with and without diabetes mellitus (DM).

Methods and results: A total of 1991 AF patients were enrolled and divided into two groups according to whether they have DM at recruitment. Baseline information was collected and a mean follow-up of 1 year was carried out. The primary outcome was defined as all-cause mortality with the secondary outcomes including cardiovascular mortality, stroke and major adverse events (MAEs). Univariable and multivariable Cox regression were performed to estimate the association between BMI and 1-year outcomes in AF patients with and without DM. 309 patients with AF (15.5%) had comorbid DM at baseline. Patients with DM were more likely to have cardiovascular comorbidities, receive relevant medications but carry worse 1-year outcomes. Multivariable Cox regressions indicated that elevated BMI was related with reduced risk of all-cause mortality, cardiovascular mortality and major adverse events. Compared to normal weight, overweight [HR (95% CI): 0.548 (0.405-0.741), p < 0.001] and obesity [HR (95% CI): 0.541 (0.326-0.898), p = 0.018] were significantly related with decreased all-cause mortality for the entire cohort. Remarkably reduced all-cause mortality in the overweight [HR (95% CI): 0.497 (0.347-0.711), p < 0.001] and obesity groups [HR (95% CI): 0.405 (0.205-0.800), p = 0.009] could also be detected in AF patients without DM, but not in those with DM.

Conclusion: Elevated BMI was associated with reduced mortality in patients with AF. This association was modified by DM. The obesity paradox confined to AF patients without DM, but could not be generalized to those with DM.

Keywords: All-cause mortality; Atrial fibrillation; Body mass index; Diabetes mellitus.