The impact of body weight and diabetes on new-onset atrial fibrillation: a nationwide population based study

BACKGROUND: Being obese or underweight, and having diabetes are important risk factors for new-onset atrial fibrillation (AF). However, it is unclear whether there is any interaction between body weight and diabetes in regard to development of new-onset AF. We aimed to evaluate the role of body weight status and various stage of diabetes on new-onset AF. METHODS: This was a nationwide population based study using National Health Insurance Service (NHIS) data. A total of 9,797,418 patients who underwent national health check-ups were analyzed. Patients were classified as underweight [body mass index (BMI) < 18.5], normal reference group (18.5 ≤ BMI < 23.0), upper normal (23.0 ≤ BMI < 25.0), overweight (25.0 ≤ BMI < 30.0), or obese (BMI ≥ 30.0) based on BMI. Diabetes were categorized as non-diabetic, impaired fasting glucose (IFG), new-onset diabetes, diabetes < 5 years, and diabetes ≥ 5 years. Primary outcome end point was new-onset AF. New-onset AF was defined as one inpatient or two outpatient records of International Classification of Disease, Tenth Revision (ICD-10) codes in patients without prior AF diagnosis. RESULTS: During 80,130,161 patient*years follow-up, a total of 196,136 new-onset AF occurred. Obese [hazard ration (HR) = 1.327], overweight (HR = 1.123), upper normal (HR = 1.040), and underweight (HR = 1.055) patients showed significantly increased risk of new-onset AF compared to the normal reference group. Gradual escalation in the risk of new-onset AF was observed along with advancing diabetic stage. Body weight status and diabetes were independently associated with new-onset AF and at the same time, had synergistic effects on the risk of new-onset AF with obese diabetic patients having the highest risk (HR = 1.823). CONCLUSIONS: Patients with obesity, overweight, underweight, and diabetes had significantly increased risk of new-onset AF. Body weight status and diabetes had synergistic effects on the risk of new-onset AF. The risk of new-onset AF increased gradually with advancing diabetic stage. This study suggests that maintaining optimal body weight and glucose homeostasis might prevent new-onset AF.