Background 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. Methods 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. Results 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. Conclusion 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.
Mirghani et al. (Wed,) studied this question.