Comparative Effects of GLP-1 Receptor Agonists and Metformin on Glaucoma Risk in Type 2 Diabetes Patients

Abstract

PurposeTo compare effects of glucagon-like peptide-1 (GLP-1) receptor agonists and metformin on the risk of primary open-angle glaucoma (POAG), ocular hypertension, and the need for first-line glaucoma treatments in patients with type 2 diabetes. DesignA retrospective cohort study was conducted using electronic medical records (EMR) data from the from an international electronic health record network, covering a period from May 2006 to May 2024. ParticipantsPatients diagnosed with type 2 diabetes mellitus (T2DM) who were treated with either GLP-1 receptor agonists or metformin. MethodsData from 120 healthcare organizations across 17 countries were analyzed. Patient outcomes were assessed at 1, 2, and 3 years. Propensity score matching (PSM) was used to balance covariates such as demographics, comorbidities, and medication usage. Risk ratios (RR) with 95% confidence intervals (CI) were calculated. Main Outcome MeasuresIncidence of POAG, ocular hypertension, and the need for first-line treatments including beta-blockers, prostaglandin analogues, brimonidine, brinzolamide, dorzolamide, netarsudil, and laser trabeculoplasty. ResultsAfter PSM, both groups included 61,998 patients at the 1-year follow-up, 27,414 at the 2-year follow-up, and 14,100 at the 3-year follow-up. Patients treated with GLP-1 receptor agonists had a significantly decreased risk of developing POAG compared to those on metformin at 1 year (RR 0.59, 95% CI 0.39-0.88), 2 years (RR 0.50, 95% CI 0.32-0.78), and 3 years (RR 0.59, 95% CI 0.37-0.94). Similar protective effects were observed for ocular hypertension with risk reductions of 56% at 1 year (RR 0.44, 95% CI 0.31-0.62), 57% at 2 years (RR 0.43, 95% CI 0.30-0.62), and 49% at 3 years (RR 0.51, 95% CI 0.34-0.75). The risk of first-line therapy initiation was also lower in the GLP-1 receptor agonists group at 1 year (RR 0.63, 95% CI 0.53-0.74), 2 years (RR 0.71, 95% CI 0.59-0.85), and 3 years (RR 0.75, 95% CI 0.62-0.91). ConclusionsGLP-1 receptor agonists are associated with a significantly lower incidence of POAG, ocular hypertension, and the need for first-line glaucoma treatments compared to metformin in patients with type 2 diabetes. These findings highlight the potential ocular benefits of GLP-1 receptor agonists and their expanding role in the clinical management of diabetic patients.