Beberashvili Ilia, Yermolayeva Tatyana, Katkov Anna, Garra Nedal, Feldman Leonid, Gorelik Oleg, Stav Kobi, Efrati Shai
Nephrology Division, Assaf Harofeh Medical Center, Zerifin, affiliated with the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Internal Department E, Barzilai University Medical Center Campus, Ashkelon, Israel.
Kidney Blood Press Res. 2018;43(1):98-109. doi: 10.1159/000487106. Epub 2018 Jan 31.
BACKGROUND/AIMS: Residual kidney function (RKF) is a pivotal predictor of better clinical outcomes in maintenance hemodialysis (MHD) patients. So far there has been no attempt to use bioimpedance analysis (BIA) measurements to calculate residual glomerular filtration rate (GFR) in dialysis population. We hypothesized that performing of multi-frequency BIA at the beginning and end of hemodialysis session can enable us to predict the measured residual GFR in MHD patients. Thus our aim was to develop and validate a new RKF prediction equation using multi-frequency BIA in MHD patients.
It was diagnostic test evaluation study in a prospective cohort. Participants (n=88; mean age, 66.3±13.2 years, 59.1% males) were recruited from a single hemodialysis center. A new equation (eGFRBIA) to predict RKF, utilizing BIA measurements performed pre- and post-dialysis, was generated and cross-validated by the leave-one-out procedure. GFR estimated as the mean of urea and creatinine clearance (mGFR) using urine collections during entire interdialytic period.
A prediction equation for mGFR that includes both pre- and post-dialysis BIA measurements provided a better estimate than either pre- or post-dialysis measurements alone. Mean bias between predicted and measured GFR was -0.12 ml/min. Passing and Bablok regression showed no bias and no significant deviation in linearity. Concordance correlation coefficient indicated good agreement between the eGFRBIA and mGFR (0.75, P<0.001). Using cut-off predicted mGFR levels >2 ml/min/1.73 m2 yielded an area under curve of 0.96, sensitivity 85%, and specificity 89% in predicting mGFR. The κ scores for intraobserver reproducibility were consistent with substantial agreement between first and second estimation of RKF according to eGFRBIA (weighted κ was 0.60 [0.37-0.83]).
We present a valid and clinically obtainable method to predict RKF in MHD patients. This method, which uses BIA, may prove as accurate, convenient and easily reproducible while it is operator independent.
背景/目的：残余肾功能（RKF）是维持性血液透析（MHD）患者临床预后较好的关键预测指标。迄今为止，尚未尝试使用生物电阻抗分析（BIA）测量值来计算透析人群的残余肾小球滤过率（GFR）。我们假设在血液透析治疗开始和结束时进行多频BIA能够使我们预测MHD患者的实测残余GFR。因此，我们的目的是开发并验证一种使用多频BIA的MHD患者RKF预测新方程。
这是一项前瞻性队列中的诊断试验评估研究。参与者（n = 88；平均年龄66.3±13.2岁，59.1%为男性）来自单个血液透析中心。生成了一个利用透析前和透析后进行的BIA测量值预测RKF的新方程（eGFRBIA），并通过留一法进行交叉验证。GFR通过在整个透析间期收集尿液，以尿素和肌酐清除率的平均值（mGFR）来估算。
一个包含透析前和透析后BIA测量值的mGFR预测方程比单独的透析前或透析后测量值能提供更好的估计。预测GFR与实测GFR之间的平均偏差为-0.12 ml/min。Passing和Bablok回归显示无偏差且线性无显著偏差。一致性相关系数表明eGFRBIA与mGFR之间具有良好的一致性（0.75，P<0.001）。使用预测mGFR水平>2 ml/min/1.73 m2的截断值，在预测mGFR时曲线下面积为0.96，敏感性为85%，特异性为89%。观察者内重复性的κ评分与根据eGFRBIA对RKF的首次和第二次估计之间的高度一致性相符（加权κ为0.60 [0.37 - 0.83]）。
我们提出了一种有效且临床可获得的方法来预测MHD患者的RKF。这种使用BIA的方法可能被证明是准确、方便且易于重复的，同时它不依赖于操作人员。
