Abstract: 【Abstract】 Object To explore the accuracy of bioelectrical impedance prediction equation in the evaluation of dry weight among maintenance hemodialysis (MHD) patients. Methods Dry weight of 60 MHD patients was estimated using electrical impedance value of 50 KHz frequency measured by bioelectrical impedance analyzer, combined with slope method and new 3-compartment model. Dry weight of these participants was the post-dialysis weight, measured by inferior vena cava diameter (IVCD) method which was deemed as golden standard. Another 90 individuals with matched gender, age, height, body weight and BMI were selected to construct coefficient and compare the human body parameters with MHD patient.  Results Pearson correlation coefficient between the evaluated dry weight by slope method and true dry weight was 0.991. Bland- Altman plot showed these two approaches bore poor consistency and the difference between them was far from zero. Pearson correlation coefficient between assessed dry weight by new 3-compartmental model and true dry weight was 0.993. Bland- Altman plot revealed good consistency between the two methods with stable and minor diffidence as their differences fluctuated near zero.  Conclusion Different bioelectrical impedance measuring instrument gives rise to the impact on measured data. In this study, the new 3-compartment model predicts the dry weight of MHD patients more accurately.

Key words: Bioelectrical impedance, Hemodialysis, Dry weight