NUTRITIONAL ASSESSMENT WITH BIOELECTRICAL-IMPEDANCE ANALYSIS IN MAINTENANCE HEMODIALYSIS-PATIENTS

Protein energy malnutrition is common among persons with ESRD and cont ributes substantially to morbidity and mortality, The usual methods of nutritional assessment, such as anthropometry, can be misleading beca use of altered tissue hydration. Bioelectrical impedance analysis (BIA ) has been recommended by some as a practical nutritional assessment t ool but has not been validated in patients with ESRD. Thirty-three sta ble patients on maintenance hemodialysis were evaluated in an ambulato ry clinical research center with simultaneous BIA, dual-energy x-ray a bsorptiometry, and deuterium oxide (D2O) and sodium bromide (NaBr) iso tope dilution studies. Standard determinations of total body water (TB W) and body cell mass (BCM) were obtained and compared with values est imated by BIA. Two separate outpatient BIA measurements were also obta ined approximately 2 wk before and after the clinical research center evaluation. BCM estimated by BIA was directly correlated (r = 0.92, P < 0.0001) with BCM determined by DEXA and NaBr. TBW estimated by BIA w as directly correlated (r = 0.96, P < 0.0001) with TBW determined by d euterium oxide dilution. The reactance to resistance ratio (Xc/R) deri ved from BIA was inversely correlated (r = -0.73, P < 0.0001) with the extracellular water/TBW ratio determined by NaBr/D2O. Bland-Altman an alyses showed that for TEW, BIA was in excellent agreement with D2O di lution. BCM was modestly underestimated by BIA compared with the dual- energy x-ray absorptiometry/NaBr standard and was adjusted by linear r egression. The coefficients of variation on repeated BIA measurements were below 4%, demonstrating test-retest reliability. BIA is a valid a nd reliable method of nutritional assessment in maintenance hemodialys is patients.