A comparison of three methods for estimating height in the acutely ill elderly population

Abstract

Background. Most estimates of nutritional status rely on accurate recording of not only body weight but also height. Standing height is difficult to measure accurately in older adults due to mobility problems and kyphosis. Surrogate methods have been developed to estimate height including arm-span, demi-span and knee height. There are currently little data on the accuracy of these methods in the sick elderly population or which method is the most suitable in the clinical situation. Objective. To compare three commonly used clinical measurements that can estimate height and analyse their agreement with current height. Also to evaluate which method can be used most frequently. Methods. We used data collected as part of a larger intervention trial, in which elderly in-patients (over 65 years), were measured for demi-span, half arm-span, knee height and standing height. Results. The results showed that demi-span and half arm-span could be measured in the largest proportions of our population, 75.6 and 72.3%, respectively. The correlation coefficients were high for all three estimates of height, r = 0.86 for demi-span, r = 0.87 for arm-span, and r = 0.89 for knee height (P < 0.0001 for all three). However, agreement analysis demonstrated very poor agreement between standing height and all the methods of estimation. The mean differences were 4.33 cm for demi-span, 7.04 cm for arm-span and -0.6 cm for knee height.