Cystatin C for early detection of renal impairment in diabetes

Objectives: Evaluation of glomerular filtration rate is of crucial importance in diabetes. Cystatin C, a cysteine protease inhibitor seems to be an interesting parameter. Design and methods: 67 diabetic patients with normal creatinine are evaluated. Cystatin C is compared to renal markers, by reference to Cr EDTA clearance. Results: Significant correlations are found between cystatin C and creatinine (r=0.54). GFR MDRD (r=-0.47) and GFR Cr EDTA (r=-0.47). The AUC of the receiver operating curves is better for GFR MDRD (0.83) and cystatin C (0.75) than for creatinine (0.63) considering the cut off value of 80 mL/min for GFR EDTA. Conclusion: Cystatin C seems to be a more sensitive parameter than creatinine for the detection of an incipient nephropathy in diabetes. (C) 2008 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.