Underweight Is A Major Risk Factor of Atrial Fibrillation In Asian People With Type 2 Diabetes Mellitus

Background: Atrial fibrillation (AF) is prevalent in patients with type 2 diabetes mellitus (T2DM). Obesity commonly accompanies with T2DM and increases AF incidence. However, the dose-relationship of body mass index (BMI) and the risk of AF has seldom been studied in diabetes patients.Methods: This cohort study was conducted utilizing a database from National Taiwan University Hospital, a tertiary medical center in Taiwan. Between 2014 and 2019, a total of 64339 adult patients with T2DM were enrolled for analysis. The BMI was measured and categorized into several groups including underweight (BMI <18.5), normal range (18.5≤BMI <24), overweight (24≤BMI <27), obesity class 1 (27≤BMI <30), obesity class 2 (30≤BMI <35), and obesity class 3 (BMI≥35). Multivariate Cox regression models and spline regression model were employed to estimate the relationship between BMI and the risk of AF in patients with T2DM.Results: The incidence rate of AF was 1.97 per 1000 person-year during a median follow-up period of 70.7 months. In multivariate Cox regression model, by using normal BMI as reference group, individuals with underweight (HR 1.47, 95%CI 1.19-1.81, p<0.001) was significantly associated with increased risk of AF while overweight was significantly associated with reduced risk of AF (HR 0.83, 95%CI 0.76-0.91, p<0.001). The Kaplan-Meier analysis showed that the risk of AF was highest in the underweight group, followed by obesity class 3, while the overweight group had the least incidence of AF (log-rank test, p<0.001). Cubic restrictive spline model showed a “J-shaped” or “L-shape” relationship between BMI and the risk AF.Conclusions: We found that underweight carries the highest risk of AF in Asian patients with T2DM.