Serum levels of interleukin-18 in diabetic retinopathy patients: A meta-analysis

Abstract

Purpose To assess the relationship between plasma interleukin-18 (IL-18) levels and the risk of diabetic retinopathy (DR). Materials and methods PubMed, Embase, Web of science, and Cochrane were reviewed systemically from inception to August 2022. Searches were performed using a combined term that included all spellings of “diabetic retinopathy,” and “interleukin-18”. Eligible studies were retrospective studies reporting changes in IL-18 levels between the DR group and the control group. The healthy controls had no identifiable DR disease. Pooled outcomes were reported as standard mean difference (SMD) with 95% confidence intervals (CI) with a random-effects model. Heterogeneity was assessed using the I2 statistics, and it was considered significant if I2 > 75%. Publication bias was evaluated using funnel plots and Begg's and Egger's tests. A meta-analysis was conducted using STATA 12.0 (StataCorp LLC, College Station, TX, USA). Results 7 studies and four countries incorporated 160 cases, and 119 controls were incorporated in this meta-analysis. When comparing subjects without DR, those with DR tended to have higher serum IL-18 levels (SMD = 3.41, 95% CI = 1.84–4.97). Publication bias indicated that no publication bias existed in the study. Conclusions Elevated circulating IL-18 levels may be one of the significant risk factors positively correlated with the development of DR. Future studies should clarify the mechanism behind this trend.