Real-World Effectiveness and Safety of Tirzepatide in Type 1 Diabetes and Obesity: Impact on Glycaemia, Weight, and Cardiometabolic Risk Markers.

AIMS: To evaluate the effectiveness and safety of tirzepatide on glycaemia, weight, and markers of cardiometabolic risk in people with type 1 diabetes and obesity. MATERIALS AND METHODS: This retrospective cohort study compared 142 adults with type 1 diabetes (BMI ≥ 30 kg/m) initiated on tirzepatide against 50 age-, sex- and BMI-matched controls. Outcomes included changes in HbA1c, weight, total daily dose of insulin, cardiometabolic markers, and safety data including hospitalisations over 12 months. RESULTS: Participants (mean age 42.8 years, BMI 37.4 kg/m, HbA1c 64.3 mmol/mol, 32% male) were followed up for a median of 365 days. The median tirzepatide dose (72.4%) was 5 mg weekly. Compared to controls, the tirzepatide group achieved significant mean reductions in: HbA1c (6.5 mmol/mol [95% CI 3.8-9.1], p < 0.001) (0.6% [0.4-0.8]), weight (13.4 kg [11.0, 15.8], p < 0.001) and total daily insulin dose (29.9 units [16.9, 42.9], p < 0.001). Significant improvements were observed in systolic blood pressure (12.6 mmHg, p < 0.001), diastolic blood pressure (4.1 mmHg, p = 0.034), total cholesterol (0.8 mmol/L, p < 0.001), non-HDL cholesterol (0.6 mmol/L, p < 0.001) and triglycerides (0.7 mmol/L, p < 0.001) compared to controls. While side effects were common, 89.4% continued on tirzepatide at 1 year. There was no between-group difference in severe hypoglycaemia, ketoacidosis nor hospitalisation rates. CONCLUSIONS: In a real-world setting, tirzepatide significantly improves glycaemia, weight, and markers of cardiometabolic risk in people with type 1 diabetes and obesity with a reassuring safety profile. These findings warrant large-scale RCTs to evaluate long-term cardiovascular outcomes in this high-risk population.