Effectiveness of Semaglutide and Tirzepatide in Overweight and Obese Adults with Type 1 Diabetes

Objective: Adults with type 1 diabetes (T1D) are increasingly overweight or obese, in part due to intensive insulin therapy. Newer non-insulin medications targeting both hyperglycemia and weight loss are approved for people with type 2 diabetes. These drugs also reduce cardiovascular disease, the major cause of mortality in people with diabetes. We assessed the real-world use of semaglutide and tirzepatide, in adults with T1D followed in a specialty diabetes clinic. Materials and Methods: This retrospective chart review included 100 adults who were prescribed semaglutide or tirzepatide (50 each) and 50 controls frequency matched for age, sex, diabetes duration, body mass index, and glycosylated hemoglobin (HbA1c) and who did not receive any weight loss medications during the study period. Data were collected prior to initiation of weight loss medications (baseline) and then for up to 1 year for each patient. Results: Matching characteristics did not differ between cases and controls. There were declines in weight in both semaglutide (-19.2 ± standard error (SE) 2.9 lbs. [9.1% body weight lost]) and tirzepatide (-49.4 ± SE 3.0 lbs. [21.4% body weight lost]) groups, and HbA1c decreased in both semaglutide (-0.54 ± SE 0.14%, P = 0.0001) and tirzepatide users (-0.68 ± SE 0.16%, P < 0.0001) over 12 months. Weight and HbA1c didn't change in controls. Conclusions: We observed weight loss of 9.1% and 21.4% and improved glucose control in semaglutide and tirzepatide users, respectively, after 1 year of off-label use. As off-label use of these drugs is increasing in patients with T1D, larger, prospective safety and efficacy trials are needed.