AIMS: To conduct a meta-analysis of randomized controlled trials (RCTs) to evaluate the effect of glucagon-like peptide-1 receptor agonists (GLP-1RAs) on glycated haemoglobin (HbA1c) and continuous glucose monitoring (CGM) metrics as an adjunct to insulin therapy in adults with type 1 diabetes mellitus (T1D).
METHODS: A systematic literature search was conducted through Medline (via PubMed), Cochrane Library, and Google Scholar up to 27 May 2024. Dual-independent study selection, data extraction, and quality assessment were performed. Results were summarized using random-effects meta-analysis.
RESULTS: Six RCTs were identified, involving a total of 378 individuals with T1D. The use of GLP-1RAs in addition to standard insulin therapy was associated with a significant reduction in HbA1c (mean difference [MD] -0.21%, 95% confidence interval [CI] -0.36 to -0.06; p = 0.007) and a similar time in range (TIR) compared to placebo (MD -0.22%, 95% CI -2.39 to 1.95; p = 0.84). GLP-1RA therapy resulted in a significantly higher time below range (MD 1.13%, 95% CI 0.50 to 1.76; p < 0.001) and a lower time above range compared with placebo (MD -1.83%, 95% CI -2.51 to -1.15; p < 0.001). Nonsignificant differences were noted for the secondary outcomes, including the mean amplitude of glucose excursion, continuous overall net glycaemic action for 60 min, mean daily glucose, coefficient of variation, and mean standard deviation of weekly glucose levels.
CONCLUSION: Our findings suggest that, in individuals with T1D, add-on therapy with GLP-1RAs does not confer significant benefits in terms of CGM metrics and is associated with a longer time below the target glycaemic range.
