Compound danshen dripping pills for diabetic retinopathy in patients with type 2 diabetes: A superiority, randomized controlled trial

BACKGROUND Compound danshen dripping pill (CDDP), an approved treatment for non-proliferative diabetic retinopathy (NPDR) in China, has demonstrated potential in both preclinical and clinical studies. However, its efficacy in NPDR has not been validated through large clinical trials. AIM To evaluate the therapeutic efficacy and safety of CDDP in NPDR. METHODS This randomized, placebo-controlled, double-blind, multicenter study included 484 NPDR patients across 16 centers in China from November 2013 to July 2017. Eligible NPDR patients were randomly assigned to the CDDP and placebo groups at a ratio of 3:1. The intervention lasted for 24 weeks. The primary outcome was the overall effective rate of fundus changes at 24 weeks, assessed through retinal microvascular status, the number of hemorrhages, and exudation area. Secondary outcomes included retinopathy severity, traditional Chinese medicine (TCM) symptoms, macular edema, and corrected visual acuity. The full analysis set (FAS) included all enrolled cases who were randomized and administered at least one study drug. RESULTS Of the 484 randomized participants, 483 (362 and 121 in the CDDP and placebo groups, respectively) were included in the FAS. At 24 weeks, the overall effective rate in the CDDP group was 77.07%, significantly higher than 53.72% found in the placebo group (P < 0.001). Results remained consistent after adjusting for central effects and baseline HbA1c. Additionally, CDDP outperformed placebo in improving retinal lesion severity, microaneurysms, hemorrhages, diabetic macular edema, and TCM symptoms. The frequencies of adverse events detected by laboratory tests did not significantly differ between the two groups. CONCLUSION CDDP significantly and effectively alleviates NPDR. Future research should focus on assessing long-term outcomes.