Traditional chinese medicine for diabetic retinopathy: A systematic review and meta-analysis

BACKGROUND: Traditional Chinese medicine (TCM) has been used to treat diabetic complications including diabetic retinopathy for many years. OBJECTIVES: This review was performed to systematically assess the efficacy and safety of TCM for treating non- proliferative diabetic retinopathy (NPDR). METHODS: Retrieval from 7 electronic databases was conducted to determine eligible trials published until March 1, 2018. Randomized controlled trials of NPDR that comparing compound Chinese medicine containing the therapeutic method of activating blood and remove stasis versus controls were included for analysis. Primary outcomes were progression of retinopathy. Secondary outcomes included visual acuity, mean defect of visual field, micro-aneurysms, hemorrhage areas, exudates, capillary nonperfusion areas, hemorheological indicators, oscillatory potentials (Ops), glycated haemoglobin (HbA1c), and adverse events. Data extraction and quality assessment were performed. Results expressing as risk ratios (RRs) or mean differences (MD) were analyzed with a fixed- or random- effect model. I(2) statistics were used to assess heterogeneity. RESULTS: A total of 33 trials and 3373 participants were included. Findings revealed that no included studies reported the progression of retinopathy. Compared with conventional medicine, TCM was significantly better at improving visual acuity (MD, −0.10; 95% confidence interval [CI] −0.16 to −0.05) and Ops (MD, −4.68, 95% CI −8.51 to −0.85), and reducing the mean defect of visual field (MD, −1.43; 95%CI, −2.17 to −0.68), micro-aneurysms (MD, −4.51; 95% CI, −6.23 to −2.79), hemorrhage areas (MD, −0.62; 95% CI, −1.06 to −0.19), plasma viscosity (MD, −0.10; 95% CI, −0.20 to 0.00), and HbA1c (MD, −0.22; 95% CI, −0.42 to −0.03). Compared with placebo, TCM was also associated with a decline in the number of microaneurysms (MD, −4.35; 95% CI, −6.25 to −2.45), exudates (MD, −0.17; 95% CI −0.31 to −0.03), capillary nonperfusion areas (MD, −0.18; 95% CI, −0.31 to −0.04), and HbA1c (MD, −0.88; 95% CI, −1.44 to −0.32). Compared with blank groups, TCM was superior at decreasing the mean defect of visual field (MD, −0.87; 95% CI −0.95 to −0.79) and the numbers of micro-aneurysms (MD, −3.35; 95% CI, −4.73 to −1.97). Adverse events were also assessed. CONCLUSION: Activating blood compound Chinese herbal medicine could help to improve visual acuity, micro-aneurysms and HbA1c. Further trials are needed to provide more reliable evidence.