Time in range and serum cystatin C as predictors of diabetic kidney disease in patients with type 2 diabetes

Abstract Objectives Time in range (TIR) has become a new research focus in blood glucose management and is expected to be a new indicator to evaluate the effect of blood glucose control and predict the complications of diabetes. However, data evaluating its association with microvascular complications, especially diabetic kidney disease (DKD), are lacking. Therefore, this study aimed to investigate the relationship between TIR and serum cystatin C (Cys C) and DKD. Methods Two hundred patients with type 2 diabetes mellitus (T2DM) were included. Demographic and anthropometric data as well as blood and urine samples were collected. Serum Cys C concentration was determined. TIR (glucose 70–180 mg/dL) was monitored. Independent variables of DKD were evaluated by multiple logistic regression analysis, the diagnostic value of TIR and serum Cys C in DKD was assessed by ROC curve analysis, and the correlation between TIR and serum Cys C and other biochemical indicators was analyzed by Spearman correlation method. Results TIR decreased and Cys C increased with DKD progression in patients with T2DM. TIR and Cys C were independent predictors of DKD. The combined detection of TIR and Cys C had better diagnostic performance of DKD. A positive correlation existed between serum Cys C and course of disease, while a negative correlation was observed between estimated glomerular filtration rate (eGFR) and serum Cys C. Conclusions TIR and serum Cys C are associated with DKD and are expected to be potential markers for DKD diagnosis.