Use of bioelectrical impedance for the nutritional assessment of chronic hemodialysis patients.

Although malnutrition poses a significant risk to the well-being of chronic hemodialysis patients, their nutritional assessment is usually empirical. We studied body composition by bioelectrical impedance (BEI) prospectively in 39 patients followed for 5-12 months. BEI correctly discriminated between underweight and overweight patients in terms of fat mass (21 +/- 5 vs. 34 +/- 10%; p = 0.002), lean body mass (78 +/- 4 vs. 67 +/- 10%; p = 0.004) and total body water (57 +/- 3 vs. 49 +/- 7%; p = 0.002), respectively. Serial body weights did not correlate with changes in lean body mass (LBM) as measured by BEI. While 28% of patients lost weight, 41% lost LBM. Most striking is the contrast between the patients who showed no change in LBM by BEI and those whose body weight remained neutral (3 vs. 28%). BEI is a most sensitive clinical tool for assessing changes in LBM in hemodialysis patients.