Systematic review and meta-analysis of the related factors for diabetic retinopathy

Background: The related factors of diabetic retinopathy (DR) had attracted the attention of many scholars, and a large number of articles had been published, but the research results were not consistent. A meta-analysis was conducted to synthesize recent evidence, aiming at exploring the relationship between DR and multiple risk factors. Methods: The China National Knowledge Infrastructure, VIP, Wanfang, PubMed, Embase, Medline, and Cochrane databases were searched. The English and Chinese keywords included diabetes mellitus, DM, diabetic retinopathy, DR, and risk factors. In case-control study, the subjects are DR patients and NDR patients. In the cohort study, the subjects were diabetic patients. Measures in the intervention and control groups were described in detail. The methodological quality of the included literature was assessed using the Newcastle-Ottawa Scale (NOS). Egger's test is used to identify publication bias. With odds ratio (OR) as the effect index, heterogeneity test was conducted, and fixed effect model or random effect model was selected to calculate the combined OR and 95% CI. Results: The meta-analysis included 12 literatures and 13 related risk factors, of which 4 (33.33%) were cohort studies and 8 (66.66%) were case-control studies. NOS shows that there are 7 references with 8 points (58.33%), 4 references with 7 points (33.33%) and I reference with 6 points (8.33%). The risk factors associated with the occurrence of DR were: course of diabetes (OR =1.03, 95% CI: 1.02-1.03), systolic blood pressure (OR =1.01, 95% CI: 1.01-1.02), body mass index (OR =0.96, 95% CI: 0.94-0.99), HbA1c (OR =1.08, 95% CI: 1.06-1.10), total cholesterol (OR =1.20, 95% CI: 0.98-1.46), high-density lipoprotein cholesterol (OR =1.74, 95% CI: 1.19-2.56), fasting blood glucose (OR =1.19, 95% CI: 1.13-1.26), and hypertension (OR =1.25, 95% CI: 1.07-1.47), and the overall effect test results were statistically significant. Sensitivity analysis results show that the random effect model is used for meta-analysis of all Meta, and the combined OR is 1.10, and the 95% CI is (1.05, 1.15). Discussion: The occurrence of DR was related to the course of diabetes, SBP, HbA1c, total cholesterol, high-density lipoprotein cholesterol, fasting blood glucose, and hypertension which provided a more intuitive and comprehensive scientific basis for the prevention and treatment of DR.