The ability to assess renal function in diabetes patients rapidly and early is of major importance. This study was designed to determine whether cystatin C can replace serum creatinine as the screening marker for reduced glomerular filtration rate (GFR) in type 2 diabetes patients. The study was performed on 51 type 2 diabetic patients. GFR was estimated by the plasma clearance of (99m)Tc-DTPA. The correlation between (99m)Tc-DTPA clearance and levels of serum cystatin C, serum creatinine, and creatinine clearance was determined. Sensitivity and specificity for the diagnosis of renal impairment (defined as GFR<68 ml/min) were calculated by a receiver operating characteristic (ROC) curve for serum cystatin C, serum creatinine, and creatinine clearance. The correlation coefficients with (99m)Tc-DTPA clearance were -0.744 for serum cystatin C, -0.658 for serum creatinine, and +0.625 for creatinine clearance (P<0.001). With a cutoff value of 68 mL/min, the area under the ROC curve (AUC) was 0.891 for cystatin C, 0.77 for creatinine, and 0.753 for creatinine clearance. The AUC was statistically different between serum cystatin C and creatinine clearance (P<0.05). The ROC plot indicates that cystatin C is superior to serum creatinine and creatinine clearance for detecting impaired GFR. Serum cystatin C appropriately reflects GFR in diabetes, and is more efficacious than serum creatinine and creatinine clearance in detecting reduced GFR in type 2 diabetes patients.
Copyright 2004 Wiley-Liss, Inc.