Weight Loss-Dependent Changes in Body Composition and Bone Health in People With Obesity and Type 1 Diabetes Treated With Liraglutide, Semaglutide, or Tirzepatide.

AIMS: This study examined changes in body composition and bone mineral density (BMD) over 12 months in people with obesity and type 1 diabetes (T1D) treated with a GLP-1 receptor agonist alone (GLP-1RA) or a dual glucose-dependent insulinotropic polypeptide (GIP/GLP-1RA).

MATERIALS AND

METHODS

This real-world observational study included 70 people with obesity and T1D treated with GLP-1RA alone or dual GIP/GLP-1RA. Dual-energy X-ray absorptiometry (DEXA) was used to quantify regional and total fat mass, lean mass, bone mineral content (BMC) and BMD at baseline and after 12 months of treatment. Overall changes were quantified, and changes stratified by percentage weight loss using repeated measures analysis.

RESULTS

Over 12 months body weight (-6.33%; 95% CI: -7.92, -4.73; p < 0.001), HbA1c (-0.48%; 95% CI: -0.74, -0.22; p < 0.001), total tissue fat (-1.42%; 95% CI: -2.47, -0.36; p = 0.009), fat mass (-5.90%; 95% CI: -10.50, -1.57; p = 0.001), and lean mass (-1.75%; 95% CI: -3.50, -0.48; p = 0.005) decreased, while total BMC and BMD remained unchanged. Total lean mass loss was associated with body weight loss (R2 = 0.36, p < 0.001).

CONCLUSIONS

In people with obesity and T1D, 12-month GLP-1RA alone or dual GIP/GLP-1RA therapy resulted in clinically meaningful weight loss, improved glycaemic control, preferential fat mass reduction, modest lean mass loss, and preservation of total BMD. People achieving > 10% weight loss derived the greatest metabolic benefit without compromising bone health, although the loss of lean mass was greater.