血清胱抑素C在2型糖尿病肾病早期诊断中的价值评估

The value of serum cystatin C in the early diagnosis of type 2 diabetic nephropathy

目的 探讨血清胱抑素C在2型糖尿病肾病早期诊断中的价值.方法 应用免疫胶体金比浊法方法检测399例2型糖尿病患者和41例对照组血清胱抑素C水平,并与24 h尿微量白蛋白、内生肌酐清除率、血清尿素、肌酐及尿酸进行比较.根据24 h尿微量白蛋白水平将399例2型糖尿病病患者分为正常白蛋白尿组、微量白蛋白尿组及大量白蛋白尿组.利用受试者工作特征曲线（ROC曲线）对胱抑素C、血清尿素、肌酐进行诊断性能评价.以胱抑素C≥1.155 mg/L为界,将正常白蛋白组分为1组（胱抑素C≥1.155mg/L）和2组（胱抑素C＜1.155mg/L）并进行分析.结果 与对照组比较,2型糖尿病患者正常白蛋白尿组、微量白蛋白尿组、大量白蛋白尿组血清胱抑素C水平均升高,差异有统计学意义（P＜0.01）,且随着糖尿病患者尿白蛋白排泄的增加,胱抑素C水平也相应升高.相关分析显示2型糖尿病患者的胱抑素C与SCr、Urea、及Ccr、mALB具有较好的相关性,相关系数分别为0.779、0.782、-0.612、0.391,P＜0.01.ROC曲线分析表明胱抑素C曲线面积为0.938,高于SCr、Urea,诊断分界值为1.155 mg/L,此时诊断敏感性为85.3%,诊断特异性为97.8%,而SCr、Urea的ROC曲线面积分别为0.83及0.78.正常白蛋白尿1组的患者其血清胱抑素C、SCr、Urea、UA、mALB水平均高于2组,而Ccr低于2组水平,差异有统计学意义.结论 血清胱抑素C是糖尿病早期肾损害的灵敏指标,尤其在正常白蛋白尿排泄的糖尿病患者中定期检测Cys C可以动态观察病情的发展,及早发现肾脏的改变,对糖尿病肾脏损害的防治有重要意义.

Objective To assess the value of serum cystatin C in the early diagnosis of type 2 diabetic nephropathy. Methods Colloidal immunogolden method was used to detect levels of serum cystatin C in 399 patients with type 2 diabetes mellitus and 41 control subjects. Urinary albumin, creatinine clear rate, serum urea, creatinine, and uric acid were compared. According to the levels of urinary albumin, 399 patients were divided into normal albuminuria group, mirroalbuminuria group and macroalbuminuria group. Receiver operating characteristic curve （ROC curve） was used to evaluate the diagnostic value of cystatin C, urinary albumin, serum urea, creatinine. The normal albumin group were subdivided into group 1 （cystatin C= 1.155 mg/L）, and group 2 （cystatin C 〈 1.155 mg/L） for analysis. Results As compared with the control group, serum cystatin C levels in normal albuminuria group, microalbuminuria group, and macroalbuminuria group were increased significantly （P〈0.01）, and cystatin level also increased with elevation of urinary albumin excretion in diabetic patients. Correlated analysis showed that cystatin C had a good correlation with SCr, Urea, Ccr, and mALB, with a correlation coefficient of 0.779, 0.782, -0.612, or0.391 （P〈0.01）. ROC curve analysis showed that the area under the curve （AUC） of cystatin C was 0.938, greater than that of SCr, Urea the diagnostic boundary value was 1.155 mg/L, the diagnostic sensitivity was 85.3%, diagnostic specificity was 97.8%, while ROC＇ s curve area for SCr and Urea was 0.83 and 0.78, respectively. Serum cystatin C, SCr, Urea, UA, and mALB were higher in Normal albuminuria group 1 than in group 2, and Ccr level was lower. Conclusions Serum cystatin C is a sensitive index for early renal damage in diabetes. Detection of Cys C on a regular basis in the diabetic patients with a normal albuminuria excretion can monitor the dynamic develop- ment of disease. The early detection of renal changes has important significance in the prevention and treatment of diabetic kidney damage.