Oral Chinese medicines for treating diabetic macular edema: Protocol for a systematic search of randomized studies and meta-analysis

IntroductionThe diabetic macular edema (DME) is a relevant cause of visual impairment in diabetes. The current treatments are limited by high costs, risk of infections and damage to retinal cells. Randomized controlled studies (RCTs) have investigated oral traditional Chinese medicines (TCMs) for the treatment of DME. We aimed at determining the efficacy and safety of oral TCMs by systematically reviewing the full set of studies. Methods and analysisPublished RCTs will be searched through 12 databases until October 1, 2022. Two investigators will conduct independent literature search, data extraction and assessment of quality. The risk of bias will be judged with the version 2 of the Cochrane risk-of-bias tool. The RevMan software will be utilized to analyze data. Dichotomous data will be assessed by using odds ratios and 95% confidence intervals (CIs). We will evaluate continuous data by using weighted mean differences and 95% CIs. We are going to assess heterogeneity by Cochrans Q test and the I2 statistics. We plan sensitivity analysis and subgroup analysis to identify sources of heterogeneity. Funnel plots, Eggers tests and Beggs tests will be also performed. Protocol registration numberThe study protocol is registered on PROSPERO (CRD42022379268). Strengths and limitationsO_LIThis is the first systematic study examining the efficacy and safety of orally administered Chinese medicines for DME. C_LIO_LIWe will search randomized controlled trials in 12 databases. C_LIO_LIWe will implement subgroup analysis and sensitivity analysis to explore any source of heterogeneity. C_LIO_LIThe presence of several types of macular oedema might challenge the workload for this study. C_LI