Barroso S, Martínez J M, Martín M V, Rayo I, Caravaca F
Servicio de Nefrología, Hospital Infanta Cristina, Badajoz.
Nefrologia. 2006;26(3):344-50.
Cockcroft-Gault (CG) and Modification of Diet in Renal Disease (MDRD) formula are indirect estimates of renal function which have been widely accepted, though their accuracies have been scarcely validated in advanced chronic renal failure. The purpose of this study was to determine the accuracy (bias and precision) of these formulas in advanced CRF patients. The study group consisted of 99 unselected patients (62 +/- 15 years, 59 females) with advanced CRF. The glomerular filtration rate (GFR) was measured by Tc(99m) DTPA. Simultaneously, estimates of GFR by CG corrected for 1.73 m2 and MDRD (formula 7) were calculated. Agreement was evaluated graphically, bias was assessed by mean and median difference, and precision by median absolute differences and Bland-Altman plots. Mean GFR by DTPA, CG and MDRD were: 16.24 +/- 4.38 and 16.77 +/- 4.65 and 13.58 +/- 4.27 ml/min/1.73 m2, respectively. MDRD equation significantly underestimated GFR-DTPA (p = 0.0001). Both CG and MDRD correlated significantly with GFR-DTPA (R = 0.53 and R = 0.62, respectively). CG formula performed better than the MDRD equation with respect to bias (0.30 vs -3.24 ml/min/1.73 m2, p = 0.0001), and precision (0.58 vs. -3.11 ml/min/1.73 m2, p = 0.0001). By multiple linear regression, the best determinants of the error of the estimation by CC formula were: serum creatinine (beta = -0.58; p < 0.0001), age (beta = -0.62; p < 0.0001), and body mass index (beta = 0.26, p = 0.004), and by MDRD formula were: serum creatinine (beta = -0.38; p < 0.0001), and body mass index (beta = -0.20, p = 0.03). In conclusion, in unselected patients with advanced chronic renal failure, estimates by CC formula were more accurate than those obtained by MDRD formula. Serum creatinine was the main source of error of the estimation of GFR by both formulas, though demographic and anthropometric characteristics influenced as well on their accuracies.
Cockcroft-Gault（CG）公式和肾脏病膳食改良（MDRD）公式是对肾功能的间接估计，已被广泛接受，尽管它们的准确性在晚期慢性肾衰竭中几乎未得到验证。本研究的目的是确定这些公式在晚期慢性肾衰竭患者中的准确性（偏差和精密度）。研究组由99例未经挑选的晚期慢性肾衰竭患者组成（年龄62±15岁，女性59例）。采用Tc（99m）二乙三胺五乙酸（DTPA）测量肾小球滤过率（GFR）。同时，计算经1.73 m²校正的CG公式和MDRD公式（公式7）对GFR的估计值。通过图形评估一致性，通过均值和中位数差异评估偏差，通过中位数绝对差异和Bland-Altman图评估精密度。DTPA、CG和MDRD测得的平均GFR分别为：16.24±4.38、16.77±4.65和13.58±4.27 ml/min/1.73 m²。MDRD方程显著低估了GFR-DTPA（p = 0.0001）。CG和MDRD与GFR-DTPA均显著相关（R分别为0.53和0.62）。在偏差方面（0.30 vs -3.24 ml/min/1.73 m²，p = 0.0001）和精密度方面（0.58 vs. -3.11 ml/min/1.73 m²，p = 0.0001），CG公式比MDRD方程表现更好。通过多元线性回归，CG公式估计误差的最佳决定因素为：血清肌酐（β = -0.58；p < 0.0001）、年龄（β = -0.62；p < 0.0001）和体重指数（β = 0.26，p = 0.004），而MDRD公式的为：血清肌酐（β = -0.38；p < 0.0001）和体重指数（β = -0.20，p = 0.03）。总之，在未经挑选的晚期慢性肾衰竭患者中，CG公式的估计比MDRD公式更准确。血清肌酐是两个公式估计GFR误差的主要来源，尽管人口统计学和人体测量学特征也会影响其准确性。
