Objective To observe the correlation between homocysteine (Hcy) and serum uric acid (SUA) and retinopathy in type 2 diabetes mellitus (T2DM), preliminary study on its predictive value. MethodsA retrospective study. From January 2020 to March 2021, a total of 324 T2DM patients hospitalized in Department of Endocrinology, Cangzhou Central Hospital of Hebei Province were included. Fasting blood glucose (FBG), glycated hemoglobin (HbA1C), triglycerides (TG), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), serum creatinine (Scr), blood urea nitrogen (BUN), Hcy, SUA, peripheral blood endothelial progenitor cells (EPC), circulating endothelial cells (CEC) were counted and homeostasis model assessment for insulin resistance (HOMA-IR) was calculated. According to the absence or presence of diabetic retinopathy (DR), the patients were divided into non DR (NDR) group and DR group with 100 and 214 cases, respectively. Clinical data and laboratory biochemical indexes of the two groups were compared and observed. The logistic regression was used to analyze the independent risk factors for DR in T2DM patients. Smooth curve fitting was used to analyze the curve relationship between Hcy, SUA and DR, and ROC area (AUC) of Hcy, SUA; their combined prediction of DR in T2DM patients was calculated by receiver operating characteristic curve (ROC curve), and the predictive value of Hcy and SUA for DR in T2DM patients was evaluated. ResultsDiabetic course (t=5.380), systolic blood pressure (t=2.935), hypertension (χ2=10.248), diabetic nephropathy (χ2=9.515), diabetic peripheral neuropathy (χ2=24.501), FBG (t=3.945), HbA1C (t=3.336) and TG in DR Group (t=2.898), LDL-C (t=3.986), Scr (t=2.139), SUA (t=7.138), HOMA-IR (t=3.237), BUN (t=3.609), Hcy (t=2.363) and CEC (t=19.396) were significantly higher than those in NDR group. The difference was statistically significant (P＜0.05). EPC (t=9.563) and CPC (t=7.684) levels were significantly lower than those of NDR group, and the difference was statistically significant (P＜0.05). Logistic regression analysis showed that diabetes course, SBP, hypertension, FBG, HbA1C, LDL-C, SUA, Hcy, EPC, CPC and CEC were all independent risk factors for developing DR in T2DM patients (P＜0.05). The smooth curve fitting analysis showed that Hcy and SUA were positively correlated with the occurrence of DR. After adjusting for confounding factors, when Hcy≥15 μmol/L, the risk of DR Increased by 14% for every 1 μmol/L increase in Hcy [odds ratio (OR)=0.92, 95% confidence interval (CI) 0.88-0.98, P＜0.05]. When Hcy＜15 μmol/L, there was no significant difference (OR=0.96, 95%CI 0.92-1.08, P＞0.05). When SUA≥304 μmol/L, the risk of DR increased by 17%, every 20 μmol/L SUA increased (OR=0.80, 95%CI 0.68-0.94, P＜0.05). When SUA＜304 μmol/L, the difference was not statistically significant (OR=0.83, 95%CI 0.72-0.95, P＞0.05). ROC curve analysis results showed that the AUC values of Hcy, SUA and Hcy combined with SUA in predicting the occurrence of DR in T2DM patients were 0.775 (95%CI 0.713-0.837, P＜0.001), 0.757 (95%CI 0.680-0.834, P＜0.001) and 0.827 (95%CI 0.786-0.868, P＜0.001). Hcy combined with SUA showed better predictive efficiency. ConclusionsThe abnormal increase of Hcy and SUA levels in T2DM patients are closely related to the occurrence of DR, they are independent risk factors for the occurrence of DR. Hcy combined with SUA has high predictive value for the occurrence of DR.