GLP-1 receptor agonists reduce body mass index and total daily insulin dose in youth with type 1 diabetes: a retrospective cohort study.

OBJECTIVES: Youth with type 1 diabetes (T1D) and obesity face challenges in achieving optimal glycemic control and experience higher risk for long-term complications. While glucagon-like peptide-1 receptor agonists (GLP-1RA) have shown weight and glycemic benefits in adults with type 1 diabetes, data in pediatric populations are scarce. We report here changes in glycemia, weight, and insulin doses in youth with T1D and obesity prescribed GLP-1RA. METHODS: We conducted a single-center retrospective observational study of adolescents and young adults (ages 10-20) with T1D and obesity prescribed GLP-1RA (liraglutide, exenatide, dulaglutide, semaglutide, or tirzepatide) between 2019 and 2024. Data collected included HbA, body weight, BMI, total daily insulin dose (TDD), and continuous glucose monitoring (CGM) metrics. Linear mixed effects models assessed changes over time, adjusting for age and gender. RESULTS: Among 24 patients (75 % female, 67 % public insurance, 88 % CGM users, 67 % insulin pump users), 12 months of GLP-1RA treatment led to significant reductions in weight (-9.49 kg, p<0.0001), BMI (-3.69 kg/m, p<0.0001), and BMI Z-score (-0.30, p=0.04). CGM time-in-range increased by +7.96 % (p=0.08), and time above range (180-250 mg/dL) decreased by -3.04 % (p=0.06). TDD among pump users declined by -21.42 % (p=0.002). After approximately 16 months, HbAdecreased by -0.81 % (p=0.04). Side effects were mainly gastrointestinal and transient. CONCLUSIONS: This first longitudinal report of GLP-1RA use in youth with T1D and obesity shows clinically meaningful improvements in weight, glycemia, and insulin requirements, supporting the potential role of GLP-1RA as adjunct therapy. Larger prospective studies are needed to guide clinical practice.