Tirzepatide Is Associated With Improved Metabolic Outcomes in People With Type 1 Diabetes and Overweight or Obesity: A Retrospective Cohort Study.
Tirzepatide treatment was associated with a significant reduction in body weight and insulin requirements in adults with Type 1 diabetes and obesity, but further studies are needed to confirm these findings.
Where it sits
this study against the rest of the albiglutide corpusSummary and findings
The study evaluated the effect of tirzepatide on body weight, glycaemic control, and insulin requirements in adults with Type 1 diabetes and overweight or obesity. A total of 23 adults treated with tirzepatide were matched to 23 controls. Results indicated significant reductions in body weight and insulin dose in the tirzepatide group compared to controls.
Abstract
<h4>Aims</h4>To evaluate the effect of tirzepatide on body weight, glycaemic control, insulin requirements, continuous glucose monitoring (CGM) metrics and cardiorenal parameters in adults with Type 1 diabetes (T1D) and overweight or obesity.<h4>Materials and methods</h4>In this retrospective matched cohort study, adults with T1D, BMI ≥ 27 kg/m<sup>2</sup>, CGM use and available baseline and follow-up electronic medical record data from Royal North Shore Hospital and the Northern Sydney Endocrine Centre between 2020 and 2025 were included. Twenty-three adults treated with tirzepatide were identified and propensity score-matched to 23 control participants. Primary outcomes included changes in percentage change in body weight, HbA1c, total daily insulin dose and CGM-derived metrics from baseline to follow-up. Exploratory outcomes included changes in blood pressure and biochemical markers.<h4>Results</h4>Mean follow-up duration in the tirzepatide and control groups were 28 and 31 weeks, respectively. The most common dose of tirzepatide was 5 mg/week (52.2% participants). Compared with controls, tirzepatide was associated with greater reductions in body weight (-10.01% ± 4.74% vs. +0.69% ± 3.77%, adj-p < 0.0001) and total daily insulin dose (-21.82 ± 16.30 vs. +5.62 ± 11.63 U/day; adj-p = 0.002). From baseline to end-of-study, tirzepatide was associated with a reduction in glucose management indicator, glucose SD and daily carbohydrate intake. Other CGM, blood pressure, lipid, hepatic and renal outcomes did not differ.<h4>Conclusions</h4>In adults with T1D and overweight or obesity, adjunctive tirzepatide treatment was associated with clinically meaningful reductions in percentage body weight and insulin requirements. Larger prospective studies are needed to confirm efficacy, ensure safety and assess broader cardiometabolic effects.
Background
This paper addresses the impact of tirzepatide on metabolic outcomes in adults with Type 1 diabetes and obesity, a population that may benefit from new adjunctive therapies. Prior studies have primarily focused on Type 2 diabetes, leaving a gap in understanding for Type 1 diabetes patients. This study aims to fill that gap by evaluating specific metabolic parameters in this demographic.
Methods
The study utilized a retrospective matched cohort design, including 23 adults with Type 1 diabetes, BMI ≥ 27 kg/m², and continuous glucose monitoring data. Participants were matched to 23 control individuals based on propensity scores. The primary outcomes measured were changes in body weight, HbA1c, total daily insulin dose, and CGM metrics over a follow-up period.
Results
The primary endpoint showed a mean body weight reduction of -10.01% ± 4.74% in the tirzepatide group compared to +0.69% ± 3.77% in controls, with an adjusted p-value of < 0.0001. Additionally, the total daily insulin dose decreased by -21.82 ± 16.30 U/day in the tirzepatide group versus an increase of +5.62 ± 11.63 U/day in controls, with an adjusted p-value of 0.002.
Interpretation
The findings suggest that tirzepatide may lead to significant changes in body weight and insulin requirements, which could be clinically relevant. However, the effect sizes, while statistically significant, may not be large enough to warrant changes in clinical practice without further evidence. Confounding factors such as the small sample size and retrospective nature of the study limit the conclusions that can be drawn.
Key findings
- -10.01% ± 4.74% body weight reduction vs +0.69% ± 3.77% in controls, adj-p < 0.0001
- -21.82 ± 16.30 U/day total daily insulin dose vs +5.62 ± 11.63 U/day in controls, adj-p = 0.002
- Mean follow-up duration of 28 weeks for tirzepatide and 31 weeks for controls
- 52.2% of participants received a dose of 5 mg/week
Limitations
- small sample size of n=23 per group
- retrospective design may introduce bias
- short follow-up duration of 28-31 weeks
- no long-term safety data reported