Potential Effects of Bariatric Surgery on the Incidence of Heart Failure and Atrial Fibrillation in Patients With Type 2 Diabetes Mellitus and Obesity and on Mortality in Patients With Preexisting Heart Failure: A Nationwide, Matched, Observational Cohort Study

Background Obesity and diabetes mellitus are strongly associated with heart failure (HF) and atrial fibrillation (AF). The benefits of bariatric surgery on cardiovascular outcomes are known in people with or without diabetes mellitus. Surgical treatment of obesity might also reduce the incidence of HF and AF in individuals with obesity and type 2 diabetes mellitus (T2DM). Methods and Results In this register‐based nationwide cohort study we compared individuals with T2DM and obesity who underwent Roux‐en‐Y gastric bypass surgery with matched individuals not treated with surgery. The main outcome measures were hospitalization for HF and/or AF and mortality in patients with preexisting HF. We identified 5321 individuals with T2DM and obesity who had undergone Roux‐en‐Y gastric bypass surgery between January 2007 and December 2013 and 5321 matched controls. The individuals included were 18 to 65 years old and had a body mass index >27.5 kg/m 2 . The follow‐up time for hospitalization was until the end of 2015 (mean 4.5 years) and the end of 2016 for death. Our results show a 73% lower risk for HF (hazard ratio [HR], 0.27; CI, 0.19–0.38), 41% for AF (HR, 0.59; CI, 0.44–0.78), and 77% for concomitant AF and HF (HR, 0.23; CI, 0.12–0.46) in the surgically treated group. In patients with preexisting HF we observed significantly lower mortality in the group who underwent surgery (HR, 0.23; 95% CI, 0.12–0.43). Conclusions Bariatric surgery may reduce risk for HF and AF in patients with T2DM and obesity, speculatively via positive cardiovascular and renal effects. Obesity treatment with surgery may also be a valuable alternative in selected patients with T2DM and HF.