A total of 5,067 overweight or obese individuals 45 to 76 years old with type 2 diabetes without prevalent AF were randomized to either an intensive lifestyle intervention (ILI) designed to achieve and maintain weight loss through caloric reduction and increased physical activity or a diabetes support and education usual care group. Atrial fibrillation was ascertained from electrocardiograms at study examinations and hospitalization discharge summaries. Multivariable Cox models were used to estimate the intention-to-treat effect of the intervention adjusting for baseline covariates. During a mean follow-up of 9.0 years, 294 incident AF cases were identified. Rates of AF were comparable in the ILI and diabetes support and education groups (6.1 and 6.7 cases per 1,000 person-years, respectively, P = .42). The intervention did not affect AF incidence (multivariable hazard ratio [HR] 0.99, 95% CI 0.77-1.28). Similarly, neither weight loss nor improvement in physical fitness during the first year of the intervention was significantly associated with AF incidence: multivariable hazard ratio (95% CI) comparing top versus bottom quartile was 0.70 (0.41-1.18) for weight loss and 0.88 (0.55-1.43) for physical fitness improvement.
In a large randomized trial of overweight and obese individuals with type 2 diabetes, an ILI that induced modest weight loss did not reduce the risk of developing AF.