Yang Yi-Sun, Peng Chiung-Huei, Lin Chih-Kuang, Wang Chi-Pin, Huang Chien-Ning
Division of Endocrinology and Metabolism, Department of Internal Medicine, Chung-Shan Medical University Hospital, Chung-Shan Medical University, Taichung.
Intern Med. 2007;46(12):801-6. doi: 10.2169/internalmedicine.46.6081. Epub 2007 Jun 15.
The estimation of serum cystatin C and its practical use for the estimation of the glomerular filtration rate (GFR) in diabetic patients has been previously demonstrated, however, those studies did not use the chronic kidney disease GFR staging. Therefore, we performed this study in type 2 diabetic patients with the aim to examine the usefulness of serum cystatin C to detect early decline of GFR using the staging of chronic kidney disease defined by the National Kidney Foundation.
A total of 102 Taiwanese type 2 diabetic patients were recruited from the Chung-Shan Medical University Hospital. Morning fasting blood and urine samples were obtained for basal metabolic parameters, serum creatinine, serum cystatin C, and albumin-creatinine ratio. GFR was determined by Cockcroft-Gault equation creatinine clearance (CG-CCr).
Of the 102 type 2 diabetic patients, 67, 25, and 10 had normo-, micro-, and macroalbuminuria, respectively. Serum cystatin C was superior to serum creatinine in detecting early decline of GFR. The diagnostic accuracy of serum cystatin C was better than serum creatinine for stage 1 and 2 chronic kidney disease (CG-CCr cut-off value of 90 ml/min and 60 ml/min). Furthermore, serum cystatin C was also correlated with urine albumin excretion, which was not true with serum creatinine.
These results suggest that serum cystatin C may be an alternative serum marker for the early identification of subjects with a slight reduction of renal function, and also it may be a marker for early glomerular dysfunction in type 2 diabetes.
先前已有研究证实血清胱抑素C的评估及其在糖尿病患者肾小球滤过率（GFR）评估中的实际应用，然而，这些研究未采用慢性肾脏病GFR分期。因此，我们对2型糖尿病患者进行了本研究，旨在使用美国国立肾脏基金会定义的慢性肾脏病分期来检验血清胱抑素C检测GFR早期下降的有效性。
从中山医学大学附设医院招募了102名台湾2型糖尿病患者。采集清晨空腹血样和尿样，检测基础代谢参数、血清肌酐、血清胱抑素C和白蛋白肌酐比值。通过Cockcroft-Gault公式计算肌酐清除率（CG-CCr）来测定GFR。
在102名2型糖尿病患者中，分别有67例、25例和10例患有正常蛋白尿、微量蛋白尿和大量蛋白尿。在检测GFR早期下降方面，血清胱抑素C优于血清肌酐。对于1期和2期慢性肾脏病（CG-CCr临界值分别为90 ml/min和60 ml/min），血清胱抑素C的诊断准确性优于血清肌酐。此外，血清胱抑素C还与尿白蛋白排泄相关，而血清肌酐则不然。
这些结果表明，血清胱抑素C可能是早期识别肾功能轻度降低患者的替代血清标志物，也可能是2型糖尿病早期肾小球功能障碍的标志物。
