Diabetes and risk of glaucoma: systematic review and a Meta-analysis of prospective cohort studies

AIM: To quantify the association between diabetes and glaucoma using Meta-analysis. METHODS: PubMed and Embase were searched using medical subject headings and key words related to diabetes and glaucoma. The inclusion criteria were: 1) the study design was a prospective cohort study; 2) the exposure of interest was diabetes; 3) the outcome of interest was primary open angle glaucoma (POAG); 4) risk ratios (RR) and the corresponding 95% confidence interval (CI). Data were pooled using fixed effects models to take into account heterogeneity between studies. Seven prospective studies were selected. Diabetes increased the incidence of glaucoma by 36% (OR=1.36, 95% CI=1.25-1.50). There was no evidence of statistical heterogeneity (I-2=0, P=0.53) or publication bias (the funnel plot did not identify obvious asymmetry). RESULTS: Seven prospective cohort studies were incorporated in this Meta-analysis. The pooled RR of the association between POAG and diabetes based on the risk estimates of the seven cohort studies was 1.36 (95% CI=1.24-1.50), with no significant heterogeneity across studies (I-2=0; P=0.526). The sensitivity analysis yielded a range of RRs from 1.34 (95% CI=1.22-1.48) to 1.40 (95% CI=1.18-1.67). CONCLUSION: Diabetes is associated with a significantly increased risk of glaucoma.