The Failure of Anthropometry as a Nutritional Assessment Tool

Anthropometric measurements are commonly used to assess body composition changes and adequacy of nutritional support in the hospitalized patient. To test their utility as nutritional assessment tools in the intensive care unit (ICU) patient, body weight, triceps skinfold (TSF), mid-arm muscle circumference (MAMC). and fluid balance and intake were collected on 21 critically ill patients during their ICU stay. Correlations were sought between adequacy of nutritional support and changes over time in weight. MAMC, fluid balance, and TSF. A significant change over time in mean body weight (p < 0.0001) was seen, reflecting a mean weight loss despite a positive cumulative fluid balance of almost 20 L by day 14 for all patients (p < 0.0001). There was a significant change over time in the mean fractional intake of required calories ranging from 41.7% on observation day 1 to a peak of 84.0% on day 22 (p < 0.001). TSF and MAMC could not be obtained on a large percentage of ICU patients due to severe edema including the mid-upper arm. Obtained measurements showed no change over the study period in TSF (p = 0.24) and MAMC (p = 0.71) despite significant changes in weight (p < 0.0001). caloric intake (p = 0.0001). and cumulative fluid balance (p = 0.0001). From these data it appears that anthropometric indices of TSF and MAMC are unrelated to nutritional intake and weight in ICU patients and are therefore not of use in the nutritional assessment of this population.