Scarborough General Hospital Toronto, Toronto University, Toronto, ON, Canada.
Int Urol Nephrol. 2010 Dec;42(4):1085-92. doi: 10.1007/s11255-010-9715-x. Epub 2010 Apr 4.
The aim of this study was to examine the accuracy of the Modification of Diet in Renal Disease (MDRD) equation and the Cockcroft and Gault formula (CCrCG) in predicting total creatinine clearance achieved by residual renal function plus peritoneal dialysis in patients on chronic peritoneal dialysis.
Total creatinine clearance was defined as peritoneal creatinine clearance (PCcr) plus the average of urine urea and creatinine clearances (cGFR). Correlation analysis and Bland-Altman plot were used to establish the degree of correlation and agreement between the estimations of creatinine clearance achieved by PCcr and the average of cGFR and estimated creatinine clearance based on serum creatinine by using either MDRD equation or the Cockcroft and Gault formula.
In one hundred fifty-six measurements, mean clearances by [cGFR + PCcr], CCrCG and MDRD were: 7.9 ± 3.1, 10.6 ± 5.2 and 8.5 ± 4.9 ml/min/1.73 m(2), respectively. There was a good correlation between [cGFR + PCcr] and MDRD (r = 0.776, P < 0.05) and [cGFR + PCcr] and CCrCG (r = 0.735, P < 0.05). The mean MDRD was not significantly different from the mean clearance by [cGFR + PCcr] (difference 0.4 ± 2.9 ml/min/1.73 m(2), agreement limit -5.4-6.3 ml/min/1.73 m(2)). The CCrCG formula gave a larger difference from the mean [cGFR + PCcr] (2.8 ± 10.5 ml/min/1.73 m(2)) and a much wider agreement limit (-3.7-9.3 ml/min/1.73 m(2)). In male patients, MDRD formula provided an estimate of clearance that was similar to the mean [cGFR + PCcr] (7.9 ± 3.8 ml/min/1.73 m(2) vs. 8.2 ± 3.2 ml/min/1.73 m(2), respectively; difference 0.10 ± 1.9 ml/min/1.73 m(2), limits of agreement -3.9-3.7 ml/min/1.73 m(2)). By contrast, in female patients, the MDRD equation significantly overestimated the clearance (difference between mean estimated and mean measured clearance 1.4 ± 4.1 ml/min/1.73 m(2), limits of agreement -6.6-9.5 ml/min/1.73 m(2) P < 0.05). In conclusion, the GFR estimated by MDRD formula is similar to [cGFR + PCcr] especially in males. GFR by the CCrCG formula tended to overestimate the highest values of [cGFR + PCcr].
本研究旨在评估改良肾脏病膳食研究（MDRD）方程和 Cockcroft 和 Gault 公式（CCrCG）预测慢性腹膜透析患者残余肾功能加腹膜透析获得的总肌酐清除率的准确性。
总肌酐清除率定义为腹膜肌酐清除率（PCcr）加尿尿素和肌酐清除率（cGFR）的平均值。使用相关分析和 Bland-Altman 图，根据血清肌酐使用 MDRD 方程或 Cockcroft 和 Gault 公式，建立 PCcr 和 cGFR 平均值预测的肌酐清除率与估计的肌酐清除率之间的相关性和一致性程度。
在 156 次测量中，[cGFR+PCcr]、CCrCG 和 MDRD 的平均清除率分别为：7.9±3.1、10.6±5.2 和 8.5±4.9 ml/min/1.73 m2。[cGFR+PCcr]与 MDRD（r=0.776，P<0.05）和[cGFR+PCcr]与 CCrCG（r=0.735，P<0.05）之间存在良好的相关性。MDRD 的平均值与[cGFR+PCcr]的平均值（差值 0.4±2.9 ml/min/1.73 m2，一致性限-5.4-6.3 ml/min/1.73 m2）无显著差异。CCrCG 公式与[cGFR+PCcr]的平均值（差值 2.8±10.5 ml/min/1.73 m2）差异较大，一致性限较宽（-3.7-9.3 ml/min/1.73 m2）。在男性患者中，MDRD 公式提供的清除率估计值与[cGFR+PCcr]的平均值相似（分别为 7.9±3.8 ml/min/1.73 m2和 8.2±3.2 ml/min/1.73 m2；差值 0.10±1.9 ml/min/1.73 m2，一致性限-3.9-3.7 ml/min/1.73 m2）。相比之下，在女性患者中，MDRD 方程显著高估了清除率（平均估计值与平均实测值之间的差值为 1.4±4.1 ml/min/1.73 m2，一致性限为-6.6-9.5 ml/min/1.73 m2，P<0.05）。总之，MDRD 公式估计的 GFR 与[cGFR+PCcr]相似，特别是在男性中。CCrCG 公式的 GFR 往往高估了[cGFR+PCcr]的最高值。
