PURPOSE: Although the cardiovascular benefits of GLP-1RAs in type 2 diabetes are established, their effects in type 1 diabetes remain unclear. This study aimed to evaluate the impact of GLP-1RAs as adjunctive therapy on cardiometabolic risk factors in T1DM.
METHODS: A comprehensive search of randomised controlled trials (RCTs) was conducted in PubMed, Embase, Cochrane Library, Web of Science. The search covered all studies published from database inception to August 30, 2025. The methodology followed the PRISMA 2020 guidelines and the Cochrane Handbook for Systematic Reviews of Interventions, with eligibility criteria based on the PICOS framework. Randomised controlled trials comparing GLP-1 receptor agonists with placebo or standard insulin therapy in patients with type 1 diabetes mellitus were included.
RESULTS: A total of 21 RCTs involving 3417 patients and evaluating five different GLP-1RAs were included. Compared with the control group, GLP-1RAs significantly reduced systolic blood pressure (WMD: -2.65 mmHg, 95% confidence interval [CI]: -3.81 to -1.49, I = 0.0% and p < 0.001_effect), decreased diastolic blood pressure (WMD: -0.99 mmHg, 95% CI: -1.70 to -0.28, I = 0.0% and p = 0.006_effect) and increased heart rate (WMD: 3.90 bpm, 95% CI: 2.54 to 5.26, I = 0.0% and p < 0.001_effect). Similarly, total cholesterol (WMD: -0.15 mmol/L, 95% CI: -0.29 to -0.01, I = 0.0% and p = 0.031_effect), LDL cholesterol (WMD: -0.12 mmol/L, 95% CI: -0.22 to -0.01, I = 0.0% and p = 0.028_effect) and CRP (SMD: -0.32, 95% CI: -0.54 to -0.10, I = 0.0% and p = 0.005_effect) were significantly reduced, whereas no significant changes were observed for triglycerides, VLDL cholesterol, HDL cholesterol, TNF-α or IL-6 (all p > 0.05_effect). Previous meta-analyses have shown the efficacy and safety of GLP-1RAs in T1DM, and this study once again verified that GLP-1RAs can significantly reduce glycosylated haemoglobin (HbA1c) (WMD: -0.21% and 95% CI: -0.26 to -0.17), body weight (WMD: -3.91 kg and 95% CI: -4.53 to -3.30) and body mass index (BMI) (WMD: -1.52 kg/m, 95% CI: -1.88 to -1.16) (all p < 0.05_effect). 2 2 2 2 2 2 2
CONCLUSION: The use of GLP-1RAs as adjuvant therapy for T1DM is not only beneficial for glycaemic control and weight loss, but also can lead to important improvements in other cardiometabolic risk factors and provide valuable guidance for clinicians in making treatment decisions for this population.
