EVALUATION OF BIOELECTRICAL-IMPEDANCE FOR PROSPECTIVE NUTRITIONAL ASSESSMENT IN CYSTIC-FIBROSIS

We have compared the use of bioelectrical impedance analysis (BIA) wit h anthropometry for the prediction of changes in total body potassium (TBK) in a group (n = 31) of children with cystic fibrosis. Linear reg ression analysis showed that TBK was highly correlated (r > 0.93) with height(2)/impedance, weight, height, and fat-free mass (FFM) estimate d from skin-fold measurements. Changes in TBK were also correlated, bu t less well, with changes in height(2)/impedance, weight, height, and FFM (r = 0.69, 0.59, 0.44, and 0.40, respectively). The children were divided into two groups: those who had normal accretion of TBK (> 5%/y ) and those who had suboptimal accretion of TBK (< 5%/y). Analysis of variance showed that the significant difference in the change in TBK b etween the groups was detectable by concomitant changes in impedance a nd weight but not by changes in height, FFM, or weight and height Z sc ores. The results of this study suggest that serial BIA measures may b e useful as a predictor of progressive undernutrition and poor growth in children with cystic fibrosis. (C) Elsevier Science Inc. 1997.