Bicik Zerrin, Bahcebasi Talat, Kulaksizoglu Sevsen, Yavuz Ozlem
Department of Nephrology, Abant Izzet Baysal University, Duzce School of Medicine, Düzce, Turkey.
Clin Chem Lab Med. 2005;43(8):855-61. doi: 10.1515/CCLM.2005.144.
We determined the sensitivity, specificity, receiver operating characteristics and correlation between cystatin C (cysC) and two widely used markers of renal function, creatinine clearance and serum creatinine, in 244 patients (84 diabetics, 84 hypertensive and 76 healthy subjects). Renal failure was defined as creatinine clearance of less than either 80 or 60 mL/min. Variables were evaluated for two definitions of renal failure and compared between patient groups. Correlation coefficients with cysC were -0.87 for creatinine clearance and 0.92 for creatinine in patients with hypertension; -0.90 for creatinine clearance and 0.97 for creatinine in diabetics; and -0.61 for creatinine clearance and 0.94 for creatinine in the control group. The receiver operating characteristic curves with a cut-off value of 60 mL/min were similar for creatinine and cysC, while at 80 mL/min they were 0.626 for creatinine and 0.813 for cysC levels. We classified the patients into three groups with respect to creatinine clearance (1, >80 mL/min; 2, 60-80 mL/min; 3, <60 mL/min). Mean creatinine (p<0.0001) and cysC (p<0.0001) levels were significantly different between all the groups. Sensitivity, specificity and predictive values were higher for cysC levels, particularly in diabetics and hypertensive patients. The current study suggests that cysC is preferable for detecting temporal changes in renal function in the early stages of renal insufficiency.
我们测定了244例患者（84例糖尿病患者、84例高血压患者和76例健康受试者）中胱抑素C（cysC）与两种广泛应用的肾功能标志物——肌酐清除率和血清肌酐之间的敏感性、特异性、受试者工作特征及相关性。肾衰竭定义为肌酐清除率低于80或60 mL/分钟。针对两种肾衰竭定义对各项变量进行评估，并在不同患者组之间进行比较。高血压患者中，肌酐清除率与cysC的相关系数为 -0.87，肌酐与cysC的相关系数为0.92；糖尿病患者中，肌酐清除率与cysC的相关系数为 -0.90，肌酐与cysC的相关系数为0.97；对照组中，肌酐清除率与cysC的相关系数为 -0.61，肌酐与cysC的相关系数为0.94。肌酐和cysC以60 mL/分钟为临界值的受试者工作特征曲线相似，而以80 mL/分钟为临界值时，肌酐的曲线下面积为0.626，cysC水平的曲线下面积为0.813。我们根据肌酐清除率将患者分为三组（1组，>80 mL/分钟；2组，60 - 80 mL/分钟；3组，<60 mL/分钟）。所有组之间的平均肌酐水平（p<0.000）和cysC水平（p<0.0001）存在显著差异。cysC水平的敏感性、特异性和预测值更高，尤其是在糖尿病患者和高血压患者中。当前研究表明，cysC更适合用于检测肾功能不全早期阶段的肾功能动态变化。
