Tzamaloukas Antonios H, Murata Glen H, Vanderjagt Dorothy J, Servilla Karen S, Glew Robert H
Renal Section, New Mexico Veterans Affairs Health Care System, Department of Medicine, University of New Mexico School of Medicine, Albuquerque, New Mexico, USA.
Adv Perit Dial. 2003;19:207-11.
Protein nitrogen appearance (PNA) estimated from urea nitrogen appearance (UNA) reflects dietary protein intake and is an important index of nutrition in peritoneal dialysis (PD). Normalization of PNA by several body size indicators has resulted in discrepancies between normalized PNA (nPNA) values and other nutrition indices in PD patients with varying weight status. To test whether a particular size indicator produces nPNA values that eliminate the discrepancies, we normalized PNA values obtained at the first clearance study in 925 PD patients by weight (W), by fat-free mass (FFM) obtained from body water, by lean body mass (LBM) derived from creatinine kinetics, by desirable weight (DW), by standard weight (SW), and by adjusted edema-fee body weight (aBW). We classified patients into three groups according to W/DW: an underweight group [group I: W/DW < 0.9, n = 147 (15.9%)], a normal-weight group [group II: 0.9 < or = W/DW < 1.2, n = 506 (54.7%)], and an obese group [group III: W/DW > or = 1.2, n = 272 (29.4%)]. The UNA and PNA increased progressively from group I to group III. The W, FFM, LBM, SW, and aBW also increased progressively, and the corresponding nPNA values decreased progressively from group I to group III--all at p < 0.001. The DW did not differ significantly between the three groups. The PNA values normalized by DW were 0.91 +/- 0.21 (group I), 0.96 +/- 0.24 (group II), and 1.07 +/- 0.25 (group III), p < 0.001. Of the six size indicators tested, only DW produced values of nPNA consistent with the nutrition status of PD patients with varying weight status. Our findings indicate that DW is the proper size indicator for normalizing PNA in PD patients.
根据尿素氮表现（UNA）估算的蛋白质氮表现（PNA）反映了饮食蛋白质摄入量，是腹膜透析（PD）中一项重要的营养指标。通过多种身体尺寸指标对PNA进行标准化处理后，体重状况各异的PD患者的标准化PNA（nPNA）值与其他营养指标之间出现了差异。为了测试特定的尺寸指标所产生的nPNA值是否能消除这些差异，我们对925例PD患者首次清除率研究时获得的PNA值，分别采用体重（W）、通过身体水分得出的去脂体重（FFM）、根据肌酐动力学得出的瘦体重（LBM）、理想体重（DW）、标准体重（SW）以及调整后的无水肿体重（aBW）进行标准化处理。我们根据W/DW将患者分为三组：体重过轻组[第一组：W/DW < 0.9，n = 147例（15.9%）]、正常体重组[第二组：0.9≤W/DW < 1.2，n = 506例（54.7%）]和肥胖组[第三组：W/DW≥1.2，n = 272例（29.4%）]。UNA和PNA从第一组到第三组逐渐升高。W、FFM、LBM、SW和aBW也逐渐升高，相应的nPNA值从第一组到第三组逐渐降低——均为p < 0.001。三组之间DW无显著差异。经DW标准化处理后的PNA值分别为0.91±0.21（第一组）、0.96±0.24（第二组）和1.07±0.25（第三组），p < 0.001。在所测试的六个尺寸指标中，只有DW得出的nPNA值与体重状况各异的PD患者的营养状况相符。我们的研究结果表明，DW是使PD患者PNA标准化的合适尺寸指标。
