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 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.
Meer et al. (2026) studied this question.