Tirzepatide significantly improves glycaemia, weight, and cardiometabolic markers in Type 1 Diabetes with obesity

Managing Type 1 Diabetes (T1D) is complex, and the co-occurrence of obesity exacerbates challenges, leading to increased insulin resistance and heightened cardiometabolic risk. Standard T1D treatment, primarily exogenous insulin, often contributes to weight gain, failing to address the associated metabolic dysfunction comprehensively. This creates a critical gap in care for a high-risk population. GLP-1R and GIPR co-agonists like tirzepatide, known for their efficacy in Type 2 Diabetes and obesity, offer a potential novel therapeutic strategy by improving glucose homeostasis, promoting weight loss, and mitigating cardiovascular risks.

This retrospective cohort study evaluated 142 adults with Type 1 Diabetes and obesity (BMI ≥ 30 kg/m2) who initiated tirzepatide treatment, comparing them against 50 age-, sex-, and BMI-matched controls. Participants were followed for a median of 365 days. The median tirzepatide dose was 5 mg weekly for 72.4% of the cohort. Primary outcomes included changes in HbA1c, body weight, and total daily insulin dose, alongside various cardiometabolic markers and safety data, including hospitalizations over 12 months.

Compared to controls, the tirzepatide group achieved significant mean reductions across multiple key metrics. Glycemic control improved substantially, with a mean HbA1c reduction of 6.5 mmol/mol (0.6%) (95% CI 0.4-0.8, p < 0.001). Weight management was also highly effective, showing a mean reduction of 13.4 kg (95% CI 11.0-15.8, p < 0.001). Total daily insulin dose decreased by 29.9 units (95% CI 16.9-42.9, p < 0.001). Significant improvements were also observed in cardiometabolic risk markers: systolic blood pressure decreased by 12.6 mmHg (p < 0.001), diastolic blood pressure by 4.1 mmHg (p = 0.034), total cholesterol by 0.8 mmol/L (p < 0.001), non-HDL cholesterol by 0.6 mmol/L (p < 0.001), and triglycerides by 0.7 mmol/L (p < 0.001). While side effects were common, 89.4% of participants continued tirzepatide at 1 year, and there was no between-group difference in severe hypoglycemia, ketoacidosis, or hospitalization rates.

Tirzepatide significantly reduced HbA1c by 0.6% and weight by 13.4 kg in Type 1 Diabetes patients with obesity over 12 months, alongside substantial reductions in insulin dose and cardiometabolic risk factors.