Effects of lipid-lowering agents on diabetic retinopathy: a Meta-analysis and systematic review

AIM: To clarify this controversy and to provide evidence for application of lipid lowering agents in treatment of diabetic retinopathy(DR).METHODS: We searched the databases of Pub Med, Embase and Cochrane Library Central Register of Controlled Trials(CENTRAL) and abstracts from main annual meetings up to January 1, 2017. Google scholar and ClinicalT rials.gov were also searched for unpublished relevant studies. We included randomized controlled trials(RCTs) that studied lipid-lowering agents in type 1 or type 2 diabetes in this Meta-analysis. The primary endpoint was the progression of DR, and the secondary endpoints included vision loss, development of diabetic macular edema(DME) and aggravation of hard exudates. The pooled odds ratios(OR)with corresponding 95% confidence intervals(95%CIs) were calculated.RESULTS: After systemic and manual literature search by two independent investigators, we included 8 RCTs from 7 published articles with 13 454 participants in this Meta-analysis. The results revealed that lipid-lowering drugs were associated with reduced risk in DR progression [OR=0.77(95%CI: 0.62, 0.96), P=0.02]. Lipid-lowering agents might have protective effect on DME compared to placebo, although the difference was not statistically significant [OR=0.60(95%CI: 0.34, 1.08), P=0.09]. However, no significant differences in the worsening of vision acuity [OR=0.96(95%CI: 0.81,1.14), P=0.64] and hard exudates [OR=0.50(95%CI:0.15, 1.74), P=0.28] were found between the lipidlowering drugs and the placebo groups.CONCLUSION: In DR patients, lipid-lowering agents show a protective effect on DR progression and might be associated with reduced risk in the development of DME. However, lipid-lowering agents have no effects on vision loss and hard exudates aggravation. Further clinical trials in larger scale are required to confirm the conclusion of this study and thus justify the use of intensive control lipids with anti-lipid agents at the early stages of DR.