Impact of Metabolic Bariatric Surgery on Weight Loss and Glycemic Control in Adults With Type 1 Diabetes: A Multicenter Retrospective Cohort Study

OBJECTIVE: To assess the effect of metabolic bariatric surgery (MBS) in people living with type 1 diabetes (T1D) and obesity. RESEARCH DESIGN AND METHODS: From retrospective multicenter data, total weight loss, daily insulin requirement, HbA1c, and cardiometabolic parameters were assessed before and after surgery. Longitudinal models were used to identify response determinants. RESULTS: This study included 162 people living with T1D and obesity. One year after surgery, mean total weight loss percentage was 29.7% (interquartile range [IQR] = 29.4, 30.3). Insulin requirements dropped from 0.75 (IQR = 0.58, 1.00) units/kg/day to 0.32 (IQR = 0.23, 0.43) units/kg/day (P < 0.001), and HbA1c dropped from 64.0 (IQR = 57.0, 74.0) mmol/mol to 60.0 (IQR = 53.4, 68.0) mmol/mol (P < 0.001). LDL, HDL, total cholesterol, and triglyceride levels significantly improved after surgery (P < 0.001). Greater total weight loss was associated with reduced insulin requirements, and higher baseline HbA1c was associated with poorer postsurgery glycemic control. CONCLUSIONS: MBS was associated with substantial metabolic improvement in people with T1D and obesity, in particular in those with high HbA1c and insulin need at baseline.