Potential Benefits and Harms of Gastric Bypass Surgery in Obese Individuals With Type 1 Diabetes: A Nationwide, Matched, Observational Cohort Study

OBJECTIVE To study the potential long-term benefits and possible complications of bariatric surgery in patients with type 1 diabetes (T1D). RESEARCH DESIGN AND METHODS In this register-based nationwide cohort study, we compared individuals with T1D and obesity who underwent Roux-en-Y gastric bypass (RYGB) surgery with patients with T1D and obesity matched for age, sex, BMI, and calendar time that did not undergo surgery. By linking the Swedish National Diabetes Register and Scandinavian Obesity Surgery Registry study individuals were included between 2007 and 2013. Outcomes examined included all-cause mortality, cardiovascular disease, stroke, heart failure, and hospitalization for serious hypo- or hyperglycemic events, amputation, psychiatric disorders, changes in kidney function, and substance abuse. RESULTS We identified 387 individuals who had undergone RYGB and 387 control patients. Follow-up for hospitalization was up to 9 years. Analysis showed lower risk for cardiovascular disease (hazard ratio [HR] 0.43; 95% CI 0.20-0.9), cardiovascular death (HR 0.15; 95% CI 0.03-0.68), hospitalization for heart failure (HR 0.32; 95% CI 0.15-0.67), and stroke (HR 0.18; 95% CI 0.04-0.82) for the RYGB group. There was a higher risk for serious hyperglycemic events (HR 1.99; 95% CI 1.07-3.72) and substance abuse (HR 3.71; 95% CI 1.03-3.29) after surgery. CONCLUSIONS This observational study suggests bariatric surgery may yield similar benefits on risk for cardiovascular outcomes and mortality in patients with T1D and obesity as for patients with type 2 diabetes. However, some potential serious adverse effects suggest need for careful monitoring of such patients after surgery.