# Glucagon-like peptide-1 agonists’ effects on glycemic control, weight loss, and beta cells function in type 1 diabetes

## TL;DR

This study finds that GLP-1 agonists help reduce weight and blood sugar in type 1 diabetes patients, but they come with more side effects.

## Contribution

The study provides a meta-analysis of GLP-1 agonists' effects on T1DM, focusing on weight, HbA1c, and beta cell function.

## Key findings

- GLP-1 agonists significantly reduced weight and HbA1c in T1DM patients.
- They also decreased time spent in hyperglycemia but increased total adverse events.
- No significant change in hypoglycemia time or C-peptide levels was observed.

## Abstract

Insulin is an effective treatment for type 1 diabetes mellitus (T1DM), and a significant proportion of patients are not controlled, develop hypoglycemia, and gain weight. Therefore, adjuvant therapies to mitigate the above are highly needed. Meta-analyses on the effect of glucagon peptide agonists (GLP-1 agonists) on weight loss and HbA1c are scarce. We aimed to assess the effects of GLP-1 agonists on HbA1c, weight, and C-peptide in patients with T1DM with obesity/overweight and normal weight.

We searched PubMed, Web of Science, Cochrane Library, and Google Scholar from inception up to October 30, 2025. The keywords T1DM, GLP-1 agonists, weight, HbA1c, hyperglycemia, adverse effects, hypoglycemia, time in the range, continuous monitoring, blood glucose, C-peptide, and complications were used. We identified 904 studies; from them, 33 full texts were eligible, and 18 studies were included in the meta-analysis.

GLP-1 agonists achieved a higher reduction in weight, HbA1c, and time spent in hyperglycemia compared to controls, MD=-4.28, 95% CI, -5.06--3.49, MD=-0.4, 95% CI, -0.77--0.03, and MD=-1.98, 95% CI, -3.68--0.28, respectively. The time spent in hypoglycemia, MD = 0.08, 95% CI, -0.88-1.04, and the maximum stimulated C-peptide were not different. The total adverse events were higher in GLP-1 agonists.

GLP-1 agonists reduced weight, HbA1c, and time in hyperglycemia significantly compared to controls at the cost of total side effects. The stimulated C-peptide and hypoglycemia were not different between the two groups; further well-controlled trials investigating the role of GLP-1 agonists in newly diagnosed, and normal body weight T1DM are recommended.