Mehrotra R, Saran R, Nolph K D, Moore H L, Khanna R
Department of Medicine, University of Missouri-Columbia 65212, USA.
ASAIO J. 1997 Sep-Oct;43(5):M858-61.
The protein equivalent of nitrogen appearance normalized to standard weight was determined from urea nitrogen appearance (nPNA U) and from total Kjeldahl nitrogen appearance (nPNA K) in dialysate and/or urine in 45 predialysis patients (pre D) and in 95 patients on continuous ambulatory peritoneal dialysis (CAPD). Correlations with weekly Kt/Vurea and creatinine clearance (Ccr, L/wk/1.73 m2) were determined; renal contributions of CCr in both populations were calculated both as total CCr (A) and as CCr by GFR (CCr [B], mean of renal CCr and Curea). Correlations with weekly Kt/Vurea were significant in individual (pre D:nPNA U 0.57, p < 0.01, and nPNA K 0.37, p < 0.01; CAPD:nPNA U 0.50, p < 0.01, and nPNA K 0.43, p < 0.01) and pooled populations (nPNA U 0.54, p < 0.01 and nPNA K 0.37, p < 0.01). Correlations with neither Ccr (A) nor Ccr (B) were significant. The data also allowed comment on mathematical coupling. Ccr vs nPNA K correlations share even more mathematical couplers than does the nPNA K vs Kt/Vurea correlation, yet the correlation of nPNA K with Ccr is quite low. The authors conclude that urea is a better surrogate marker of small molecular weight toxins that inhibit protein intake in uremia, and correlations of nPNA with Kt/Vurea represent more than simple mathematical coupling.
在45例透析前患者（透析前）和95例持续非卧床腹膜透析（CAPD）患者中，根据透析液和/或尿液中的尿素氮表观清除率（nPNA U）以及凯氏定氮法测定的总氮表观清除率（nPNA K），计算出按标准体重校正后的蛋白质等效氮表观清除率。确定了其与每周Kt/Vurea和肌酐清除率（Ccr，L/周/1.73 m2）的相关性；计算了两组人群中CCr的肾脏贡献，分别以总CCr（A）和肾小球滤过率计算的CCr（CCr [B]，肾脏CCr和Curea的平均值）表示。nPNA与每周Kt/Vurea的相关性在个体（透析前：nPNA U为0.57，p < 0.01，nPNA K为0.37，p < 0.01；CAPD：nPNA U为0.50，p < 0.01，nPNA K为0.43，p < 0.01）和合并人群（nPNA U为0.54，p < 0.01，nPNA K为0.37，p < 0.01）中均具有显著性。与Ccr（A）和Ccr（B）均无显著相关性。这些数据还可用于对数学耦合进行评论。Ccr与nPNA K的相关性比nPNA K与Kt/Vurea的相关性具有更多的数学耦合因子，但nPNA K与Ccr的相关性相当低。作者得出结论，尿素是抑制尿毒症患者蛋白质摄入的小分子毒素的更好替代标志物，nPNA与Kt/Vurea的相关性不仅仅是简单的数学耦合。
