To explore the relationship between serum uric acid (SUA) combining cystatin C (Cys-C) and diabetic kidney disease (DKD) in patients with diabetic retinopathy (DR) and influencing factors.

A retrospective study was conducted on the clinical data of 217 DR patients admitted to our hospital from July 2021 to June 2022. The patients were divided into a DKD-complicating group of 54 cases and non-DKD-complicating group of 163 cases. The two groups were compared in the levels of SUA and Cys-C, and it was analyzed including the relationship between SUA combining Cys-C and DKD in patients with DR, as well as the influencing factors.

The SUA and Cys-C levels in the DKD-complicating group were significantly higher than those in the non-DKD-complicating group (P<0.05). The receiver operating characteristic (ROC) curve analysis showed that the areas under the curve (AUC) of SUA and Cys-C were 0.844 and 0.825, respectively. The sensitivity and specificity were 77.8% and 84.0% for SUA and 88.9% and 63.2% for Cys-C. The AUC of the combination of SUA and Cys-C was 0.926 with a sensitivity of 97.4% and a specificity of 77.3%. Through multivariate binary logistic analysis, the increase of SUA(95%CI: 1.001-1.049, P=0.038), Cys-C(95%CI: 1.253-4.070, P=0.036), serum creatinine(Scr, 95%CI: 1.036-1.266, P=0.008) and fundus lesionscore(95%CI: 1.231-13.482, P=0.021) were the influencing factors for DKD complication in DR patients, while albumin (ALB) and statins taking may have a potential protective role (P<0.05).

SUA and Cys-C levels were increased in DR patients complicated with DKD. The combination of SUA and Cys-C may have certain predictive value. Elevated SUA, Cys-C, Scr, and fundus lesion scores were influencing factors for the DKD complication in the patients with DR.