Comparison of bioimpedance and clinical methods for dry weight prediction in maintenance hemodialysis patients.

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 (DWClin) was evaluated under strict clinical surveillance. The whole-body resistances at 50 kHz, intra- and extracellular resistances were measured to calculate the dry weight (DWCB, DWYD and DWBCS) using each of the three equations.

Results: Neither DWCB nor DWBCS were statistically different compared to DWClin (DWCB 63.2 ± 17.2 vs. 63.1 ± 16.1 kg; DWBCS 62.8 ± 16.8 vs. 63.1 ± 16.1 kg, p > 0.05). DWYD was significantly lower than DWClin (DWYD 62.0 ± 16.1 vs. 63.1 ± 16.1 kg, p < 0.05). The bias between DWCB and DWClin was the smallest among these three methods (ΔDWCB -0.1 ± 1.4 kg; ΔDWYD 1.1 ± 2.9 kg; ΔDWBCS 0.3 ± 1.8 kg).

Conclusion: The CB equations have better consistency with clinical dry weight in MHD patients.