Relationship between serum cystatin C and glomerular filtration rate in renal transplant patients

Choi, Nak Won; Kim, Jee Hyun; Lee, Chung Sik; Lee, Chang Hwa; Kim, Gheun Ho; Kang, Chong Myung

Abstract

BACKGROUND: Serum cystatin C has been proposed to be a sensitive glomerular filtration rate (GFR) marker. This study was undertaken to evaluate correlation between serum cystatin C and GFR estimates in renal transplant recipients.
METHODS
Serum cystatin C, serum creatinine and 24-hour creatinine clearance were measured in 40 adult renal transplant recipients. Three different GFR estimates were used: 24-hour creatinine clearance, Modification of Diet in Renal Disease (MDRD) equation, and Cockcroft-Gault formula. Linear regression analysis was performed to evaluate correlations between GFR estimates and serum cystatin C, and nonparametric receiver operating characteristic (ROC) analysis was carried out to compare the diagnostic accuracy of serum cystatin C with that of serum creatinine.
RESULTS
Significant correlations were noted between each of the 3 different GFR estimates (from 24-hour creatinine clearance, MDRD equation and Cockcroft-Gault formula) and serum cystatin C. Serum cystatin C also correlated significantly with serum creatinine. In the ROC analysis, the areas under the curve for cystatin C and creatinine were not significantly different when using a cut-off GFR estimate at 60 mL/min/1.73 m2.
CONCLUSIONS
Serum cystatin C is a useful marker for the assessment of GFR in renal transplant recipients, but it is not clear whether cystatin C is superior to creatinine in detection of a mild to moderate renal impairment.