Bioelectrical Impedance Detects Apparent Changes in Nutritional Status of Orally-Supplemented Older Adults

Abstract

LEARNING OUTCOME: To list three advantages of using bioelectrical impedance analysis (BIA) for assessing the effect of nutrition therapy in older adults This study evaluated changes in nutritional status over six months after an acute care hospitalization in a sample of nutritionally-compromised older adults. Subjects from a larger study were randomly assigned to receive “standard care” or two cans of oral supplement daily. Supplement was provided and compliance was monitored by can counts during monthly in-home visits. Weight, serum albumin, triceps (TSF) and subscapular skinfolds (SSF), mid-arm circumference (MAC), and BIA were measured on all subjects at baseline and six months. Fat-free mass, fat mass, body cell mass (BCM), extracellular mass (ECM), total body water, and Na e/K e were calculated from measured reactance and resistance. A post hoc analysis was conducted on 42 subjects who had repeated BIA measurements and known compliance status to evaluate whether BIA would detect a difference in nutritional status between those individuals who took supplement and those who did not. T-tests were used to compare group differences at baseline, six months and the six-month change. Differences in fat mass, TSF, and SSF at baseline between the groups suggests that subjects with lower percent of body fat self-selected to take supplement. Although both groups showed an improvement in weight, albumin and anthropometries at six months, there were no differences between the groups. However, those who took supplement had greater six month gains in BCM, ECM/BCM ratio and Na e/K e ratio. We conclude that oral supplements can have a beneficial impact on the nutritional status of nutritionally-compromised older adults. Analysis of supplement studies need to carefully consider “compliance to treatment” in addition to “intent to treat” as patients may self-select to comply for reasons that are initially not obvious. Finally, BIA is useful for assessing changes in nutritional status of older adults that may not be detected with traditional assessment methods. Funded in part by Ross Product Division. Abbott Laboratories, Columbus, OH