Dialysis Centre SM2, Policoro, Italy.
Division of Nephrology, San Pedro de Alcantara Hospital, Cáceres, Spain.
J Nephrol. 2023 Sep;36(7):1965-1974. doi: 10.1007/s40620-023-01674-0. Epub 2023 Jun 21.
Depner and Daugirdas developed a simplified formula to estimate the normalized protein catabolic rate in patients on twice- or thrice-weekly hemodialysis (JASN, 1996). The aim of our work was to establish formulas in more frequent schedules and validate them in home-based hemodialysis patients. We realized that the structure of Depner and Daugirdas' normalized protein catabolic rate formulas has a general meaning and can be expressed as PCRn = C0/[a + b*(Kt/V) + c/(Kt/V)] + d, where C0 is pre-dialysis blood urea nitrogen, Kt/V is dialysis dose, a, b, c, d are the specific coefficients for each combination of home-based hemodialysis schedules and the day of blood sampling. The same applies to the formula that adjusts C0 (C'0) for residual kidney clearance of blood water urea (Kru) and urea distribution volume (V): C'0 = C0*[1 + (a1 + b1/(Kt/V))*Kru/V]. On this basis, we computed the six coefficients (a, b, c, d, a1, b1) for each of the 50 possible combinations and simulated a total of 24,000 weekly dialysis cycles using the Daugirdas Solute Solver software recommended by the KDOQI 2015 guidelines. From the associated statistical analyses we obtained 50 sets of coefficient values, which were validated comparing the paired normalized protein catabolic rate values (i.e., those estimated with our formulas with those modeled with Solute Solver) in 210 datasets of 27 patients on home-based hemodialysis. The mean values ± SD were 1.06 ± 0.262 and 1.07 ± 0.283 g/kg/day, respectively, with a mean difference of 0.004 ± 0.034 g/kg/day (p = 0.11). The paired values were highly correlated (R = 0.99). In conclusion, even if the coefficient values were validated in a relatively small sample of patients, they allow an accurate estimation of normalized protein catabolic rate in home-based hemodialysis patients.
德普纳和多吉达斯开发了一种简化公式，用于估计每周两次或三次血液透析患者的正常化蛋白分解率（JASN，1996 年）。我们的工作目的是建立更频繁的时间表公式，并在家庭血液透析患者中验证它们。我们意识到德普纳和多吉达斯正常化蛋白分解率公式的结构具有普遍意义，可以表示为 PCRn = C0/[a + b*(Kt/V) + c/(Kt/V)] + d，其中 C0 是透析前血尿素氮，Kt/V 是透析剂量，a、b、c、d 是每个家庭血液透析时间表和采血日组合的特定系数。适用于调整残肾清除率血液水尿素（Kru）和尿素分布容积（V）的 C0（C'0）的公式也是如此：C'0 = C0*[1 + (a1 + b1/(Kt/V))*Kru/V]。在此基础上，我们为每个 50 种可能组合中的每一个计算了六个系数（a、b、c、d、a1、b1），并使用 KDOQI 2015 指南推荐的多吉达斯溶质求解器软件模拟了总共 24000 个每周透析周期。从相关的统计分析中，我们获得了 50 组系数值，并在 27 名家庭血液透析患者的 210 个数据集的配对正常化蛋白分解率值（即，使用我们的公式与溶质求解器模型化的那些值）之间进行了验证。平均值±SD 分别为 1.06±0.262 和 1.07±0.283 g/kg/天，平均差值为 0.004±0.034 g/kg/天（p=0.11）。配对值高度相关（R=0.99）。总之，即使在相对较小的患者样本中验证了系数值，它们也可以准确估计家庭血液透析患者的正常化蛋白分解率。
