Comparison of Bioimpedance and Clinical Methods for Dry Weight Prediction in Maintenance Hemodialysis Patients

Abstract

Background: Bioelectrical impedance analysis (BIA) is a promising technique to evaluate dry weight. We compared the dry weight calculated by the three BIA equations Carlo Basile (CB) , Yanna Dou (YD) and the body composition spectroscopy (BCS) with clinical evaluation in maintenance hemodialysis (MHD) patients. Methods: The dry weight of enrolled MHD patients (DW_Clin) was evaluated under strict clinical surveillance. The whole-body resistances at 50 kHz, intra- and extracellular resistances were measured to calculate the dry weight (DW_CB, DW_YD and DW_BCS) using each of the three equations. Results: Neither DW_CB nor DW_BCS were statistically different compared to DW_Clin (DW_CB 63.2 ± 17.2 vs. 63.1 ± 16.1 kg; DW_BCS 62.8 ± 16.8 vs. 63.1 ± 16.1 kg, p > 0.05). DW_YD was significantly lower than DW_Clin (DW_YD 62.0 ± 16.1 vs. 63.1 ± 16.1 kg, p < 0.05). The bias between DW_CB and DW_Clin was the smallest among these three methods (ΔDW_CB -0.1 ± 1.4 kg; ΔDW_YD 1.1 ± 2.9 kg; ΔDW_BCS 0.3 ± 1.8 kg). Conclusion: The CB equations have better consistency with clinical dry weight in MHD patients.

Do Pre‐Hemodialysis Estimates of Extracellular Volume Excess Using Bioimpedance and N‐Terminal Brain Natriuretic Peptide Correlate With Cardiac Chamber Size Measured by Magnetic Resonance Imaging?

“…We categorized patients both in terms of absolute ECW excess, using ECW volume cut offs of less than, and more than 2.0 L of the normal ECW predicted from the ICW measured by, and also by the overhydration index (OH index) proposed by Chamney et al using their OH index cut offs of less than and more than 15% (15,22). In addition we calculated ECW excess using the equation developed by Abbas et al (13), and also the ratio of ECW/height cut offs using two standard deviations based on normative data to categorize underhydration and overhydration (11)(12)(13)(14)(15)(16)(17)(18).…”

“…To aid clinical decision making, a number of approaches using cardiac natriuretic peptides and bioimpedance have been proposed to estimate ECW excess in dialysis patients , including comparing ECW with normally hydrated tissue water content , and ratios of ECW to TBW , and ECW to height .…”