不同肾小球滤过率评估方程在慢性肾脏病中的应用

Applications of different glomerular filtration rate evaluation equations in chronic kidney disease

目的：探讨不同肾小球滤过率（GFR）评估方程在慢性肾脏病（CKD）各期的一致性和适用性，以及血清CysC值对预测GFR的价值。方法：选取CKD住院患者160例，检测患者血清中的肌酐和CysC水平。分别通过CKD—EPICr（2009），CKD—EPICysC（2012），CKD—EPICrCysC（2012）和简化MDRD方程计算预测GFR（eGFR）值。根据美国K／DOQI指南，以简化MDRD方程的eGFR值为标准将所有患者分为CKDⅠ期、Ⅱ期、Ⅲ期和Ⅳ-Ⅴ期等4个组，并分别比较各组中各公式所得eGFR的相关性和均值的差异。结果：CKDI期的CKD—EPICr方程与CKD-EPICysC方程、CKDⅡ期的简化MDRD与CKD—EPICysC方程所得eGFR无显著相关性（P值均〉0．05）；其余任意两个方程、在任意分组所得eGFR均显著正相关（P值均〈0．05）。其中，CKD—EPICr与简化MDRD方程、CKD—EPICysC与CKD—EpIcr—CvsC方程在各组均具有较高的相关性（r=0．607—0．983，P值均〈0．001）。而在CKDI期，CKD—EPICr与CKD—EPICr-CysC方程、简化MDRD与CKD-EPICysC方程、简化MDRD与CKD-EPICr-CysC方程所得eGFR相关性均较低（r值均〈0．5，P值均〈0．05）。在CKDII期，CKD-EPICr方程与CKD-EPICysC方程所得eGFR相关性较低（F0．432，P=0．011）。分别将各组中不同评估方程所得eGFR两两进行配对样本的Wilcoxon符号秩检验，在CKDⅠ-Ⅲ期三组，各评估方程所得eGFR均存在显著差异（P值均〈0．01）；其中，CKD—EPICysC方程所得eGFR最低（P值均〈0．01），CKD-EPICr-CysC方程次之（P值均〈0．01），CKD-EPICr和简化MDRD方程显著高于CKD-EPICysC和CKD-EPICr-CysC方程（P值均〈0．01）。在CKDⅣ—Ⅴ期组，CKD～EPICysC方程所得eGFR显著高于另外三个公式（P值均〈0．001），尽管该组中各方程所得eGFR中位数差值均小于5ml／（min．1．73m^2）。结论：在CKDⅠ-Ⅲ期，血清CysC值对GFR的预测有重要价值，引入血CysC值的CKD—EPICysC和CKD—EPICr—CysC方程更有利于CKD的早期诊断与筛查。在CKDⅣ—Ⅴ期，不同评估方程所得eGFR具有较高一致性。

Objective： We aim to investigate the applications of different glomerular filtration rate （GFR） evaluation equations in chronic kidney disease （CKD） and the value of serum Cystatin C （Cys C） for evaluating GFR. Methods： One hundred and sixty in-patients enrolled in this study were detected for serum creafinine and Cys C. CKD-EPI Cr equation （2009） , CKD-EPI Cys C equation （2012） , CKD-EPI Cr-Cys C equation （2012） and simplified MDtLD equation were used for evaluating the eGFR of all the patients. According to American K/DOQI guidelines, all the patients were divided to CKD stage Ⅰ , CKD stage Ⅱ, CKD stage Ⅲ and CKD stage Ⅳ- Ⅴ groups, then the eGFR values from different evaluation equations were compared respectively in each group. Results： There were significant correlations between any two equations in each group （P〈0.05） , except CKD-EPI Cr equation and CKD-EPI Cys C equation in CKD stage Ⅰ group, simplified MDRD equation and CKD-EPI Cys C equation in CKD stage Ⅱ group （P〉0.05） . Of which, there were high correlations between CKD-EPI Cr equation and simplified MDRD equation、 CKD-EPI Cys C equation and CKD-EPI Cr-Cys C equation in each group （r-=0.607-0.983, P〈0.001） . In comparison, in CKD stage Ⅰ group, the correlations between CKD-EPI Cr equation and CKD-EPI Cr-Cys C equation, simplified MDRD equation and CKD-EPI Cys C equation, simplified MDRD equation and CKD-EPI Cr-Cys C equation were low （r 〈0.5, P〈0.05） . In CKD stage Ⅱ group, the correlation between CKD-EPI Cr equation and CKD-EPI Cys C equation was also low （r=0.432, P= 0.011） . Paired-sample signed rank test was used respectively to compare eGFR values from different evaluation equations in each group. In groups of CKD stage Ⅰ -Ⅲ, there was significant difference between eGFR values from different equations （P〈0.01） . There into, the eGFR values from CKD-EPI Cys C equation were the lowest （P〈0.01） , the values from CKD-EPI Cr and simplified MDRD equations were significantly higher than that from CKD-EPI Cys C and CKD-EPI Cr-Cys C equations （P〈0.01） .In CKD stageⅣ-Ⅴ group, the eGFR values from CKD-EPI Cys C equation were statistically higher than those from three other equations （P〈0.001） , despite all the median differences were less than 5 ml/（min.1.73 m^2） . Conclusion： In CKD stage Ⅰ -Ⅲ, serum Cys C is valuable for evaluating GFR, CKD-EPI Cys C and CKD-EPI Cr-Cys C equations, which introduce serum Cys C, are more conducive to early diagnosis and screening of CKD. In CKD stage Ⅳ- Ⅴ, eGFR values from different equations are of high consistency.