Interleukin-6 and Diabetic Retinopathy: A Systematic Review and Meta-Analysis

• Published in: Current eye research Vol. 44; no. 5; pp. 564 - 574
• Main Authors: Yao, Yang, Li, Rong, Du, Junhui, Long, Lihui, Li, Xiangnan, Luo, Na
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 04.05.2019
• Subjects: diabetic retinopathy; Diabetic Retinopathy - metabolism; Humans; Interleukin-6; Interleukin-6 - physiology; meta-analysis; meta-analysis; diabetic retinopathy; Interleukin-6
• ISSN: 0271-3683; 1460-2202
• DOI: 10.1080/02713683.2019.1570274

Background: Interleukin-6 (IL-6) is produced by a variety of cells involved in inflammation and acts as local intensification signals in pathological processes associated with chronic eye inflammation. This meta-analysis was performed to provide a better understanding of the relationship between IL-6 and diabetic retinopathy. Methods: The study was started with systematic search for literatures by using the PubMed, Web of Science and Embase online databases. The standard mean difference (SMD) and its 95% confidence intervals (CIs) were was included and then pooled with a random effects model. Results: Thirty-one articles, containing1099 DR patients and 1010 controls, were included in this meta-analysis. The level of IL-6 in the DR group was found to be higher than that in the control group (SMD: 2.12, 95% CI: 1.53−2.70, p < 0.00001).Obvious heterogeneity existed between the studies (p < 0.00001, I 2  = 96%). So a subgroup analysis and sensitivity analysis were performed. Removing the sensitivity studies, the stability of the overall treatment effect was good. Subgroup analysis showed that the levels of IL-6 in case group were observed to be higher than those in the control group; and the IL-6 levels in the proliferative diabetic retinopathy (PDR) group were also higher than those in the non-proliferative diabetic retinopathy (NPDR) group. (SMD: 0.78, 95% CI: 0.26-1.31, p=  0.003) Conclusion: The results from this current meta-analysis indicated that increased level of IL-6 generally exist in DR patients. And it may associated with the severity of DR. However, large-scale and high-quality studies in future are required to confirm the present findings.