Tzamaloukas Antonios H, Murata Glen H, Vanderjagt Dorothy J, Servilla Karen S, Glew Robert H
Medicine Service, New Mexico Veterans Affairs Health Care System, Albuquerque, USA.
Adv Perit Dial. 2005;21:13-6.
To test the precision of estimates of body water and urea clearance in peritoneal dialysis (PD), we compared, in 925 PD patients who underwent formal urea kinetics studies, estimates of V and Kt/V urea obtained by the use of the Watson, Hume, and Sahlgrenska anthropometric formulas and two novel formulas, one (Vcreat) computed using fat-free mass (FFM) estimated from creatinine kinetics as 0.73 x FFMcreat, and the other (VBMI) calculated as 0.73 x FFM(BMI) where FFM(BMI) was obtained by the Gallagher formula, which estimates body composition as a function of body mass index (BMI). Comparisons by twos were performed using the paired t-test and the Wilcoxon sign rank test with the Bonferroni correction for multiple (n=10) comparisons. The results for V (liters) were Watson, 36.7 +/- 7.1; Hume, 37.3 +/- 7.3; Sahlgrenska, 36.8 +/- 7.6; Vcreat, 32.2 +/- 9.8; and VBMP 37.2 +/- 7.8. With the exception of V(BMI) and V(Hume) which did not differ, all other values differed (p < 0.001) from one another regardless of whether a parametric or nonparametric comparison was performed. The results for weekly total Kt/V urea were Watson, 2.05 +/- 0.57; Hume, 2.03 +/- 0.57; Sahlgrenska, 2.06 +/- 0.59; from Vcreat 2.42 +/- 0.71; and from V(BMP) 2.03 +/- 0.58. All of those values differed from one another (p < 0.001) by both methods of comparison. Using cut-off values (1.50, 1.75, and 2.00) as indices of adequate total weekly Kt/V urea, the discrepancies between any two estimates by the five studied formulas varied in the range 1.1% - 34.2%. Despite numerically close mean values, estimates of V based on various anthropometric formulas differ substantially and cause substantial discrepancies in the classification of Kt/V urea as inadequate or adequate. This lack of precision, added to the known lack of accuracy of the estimates, confounds the interpretation of the clinical relevance of urea kinetic estimates in PD.
为了测试腹膜透析（PD）中身体水分和尿素清除率估计值的精确度，我们在925例接受正式尿素动力学研究的PD患者中，比较了使用沃森（Watson）、休谟（Hume）和萨尔格伦斯卡（Sahlgrenska）人体测量公式以及两个新公式所得到的V和Kt/V尿素估计值。其中一个新公式（Vcreat）使用根据肌酐动力学估计的去脂体重（FFM）计算得出，即0.73×FFMcreat；另一个新公式（VBMI）计算为0.73×FFM(BMI)，其中FFM(BMI)通过加拉格尔公式获得，该公式根据体重指数（BMI）估计身体成分。采用配对t检验和威尔科克森符号秩检验进行两两比较，并采用Bonferroni校正进行多次（n = 10）比较。V（升）的结果分别为：沃森公式，36.7±7.1；休谟公式，37.3±7.3；萨尔格伦斯卡公式，36.8±7.6；Vcreat公式，32.2±9.8；VBMP公式，37.2±7.8。除了V(BMI)和V(Hume)没有差异外，无论进行参数比较还是非参数比较，所有其他值相互之间均存在差异（p < 0.001）。每周总Kt/V尿素的结果分别为：沃森公式，2.05±0.57；休谟公式，2.03±0.57；萨尔格伦斯卡公式，2.06±0.59；Vcreat公式，2.42±0.71；V(BMP)公式，2.03±0.58。通过两种比较方法，所有这些值相互之间均存在差异（p < 0.001）。使用临界值（1.50、1.75和2.00）作为每周总Kt/V尿素充足的指标，五个研究公式中任意两个估计值之间的差异在1.1% - 34.2%范围内。尽管平均值在数值上接近，但基于各种人体测量公式的V估计值存在显著差异，并在将Kt/V尿素分类为不足或充足时导致显著差异。这种缺乏精确度的情况，再加上已知估计值缺乏准确性，使得对PD中尿素动力学估计值的临床相关性解释变得混乱。
