Traditional Chinese Patent Medicine Qi Zhi Jiang Tang Capsule Treatment For Non-Proliferative Diabetic Retinopathy: Study Protocol For A Randomized Controlled Trial

Background: Diabetic retinopathy is the most frequently occurring complication of diabetes mellitus and remains a leading cause of vision loss globally. Conventional treatments are focused on advanced stage of disease, targeting the early and potentially reversible retinal injury is a promising strategy for delaying non-proliferative diabetic retinopathy (NPDR). Here, we investigated the efficacy and safety of Qizhi Jiangtang capsule (QZJC), a kind of traditional Chinese patent medicine, for patients with NPDR. Methods: This study is a randomized, single-blind, placebo-controlled, multi-center clinical trial. A total of 200 participants will be randomly assigned in a 1:1:1:1 ratio to QZJC plus calcium dobesilate (CaD) group, QZJC placebo plus CaD group, QZJC group or QZJC placebo group. The treatment duration lasts 24 weeks. The primary outcome is the changes in grading of retinal microvascular injury before and after treatment. The secondary outcome will be changes in the vision, glycolipid, blood pressure, urinary albumin excretion rate and improvement of traditional Chinese medicine symptoms. All statistics will be two-sided tests, P < 0.05 is considered statistically significant. Discussion: We postulate that NPDR patients will benefit from QZJC. If successful, this work will provide preliminary evidence that QZJC could delay the progress of DR. Trial registration: Chinese Clinical Trial Registry no. ChiCTR1900023506. Registered 31 May 2019. The Version identifier is 2018121702.