Efficacy and safety of curcumin in diabetic retinopathy: A protocol for systematic review and meta-analysis

Background: Diabetic retinopathy (DR) is one of the most common complications of diabetes and has become a major global cause of blindness. Curcumin, an extract of Curcuma longa (turmeric), is effective in preventing and treating diabetes. Recent studies have shown that curcumin can delay DR development. However, there has been no systematic review of its treatment of DR. This study will conduct a systematic review and meta-analysis of currently published randomized controlled trials (RCT) of curcumin for treating DR patients to evaluate its efficacy and safety. Methods: We will search the relevant studies of curcumin in the treatment of DR in PubMed, Medline, EMBASE, Cochrane Library, China National Knowledge Infrastructure (CNKI), VIP, and Wanfang databases from their respective inception dates to May 2022. A meta-analysis of the data extracted from qualified RCTs will be conducted, including the progression of DR, visual acuity, visual field, macular edema, quality of life, and adverse events. The meta-analysis will be performed using Review Manager 5.4.1 software, and the results will be based on either random-effects or fixed-effects models, depending on the heterogeneity. The Grading of Recommendations, Development, and Evaluation (GRADE) system will be used to evaluate the reliability and quality of evidence. Results: The results of this study will provide sound and high-quality evidence for the efficacy and safety of curcumin in the treatment of DR. Conclusion: This study will be the first meta-analysis to comprehensively assess the efficacy and safety of curcumin in the treatment of DR and will provide helpful evidence for the clinical management of this disease. Systematic review registration: INPLASY202250002.