Background: It is unclear whether serial measures of body weight are valid indicators of nutritional status in older patients recovering from illness. Objectives. Investigate the relative influence of nutrient intake and changes in peripheral edema on weight change.
Methods: A prospective cohort study of 404 older men (mean age = 78.7±7.5 years) admitted to a transitional care unit of a Department of Veterans Affairs nursing home. Body weight and several indicators of lower extremity edema were measured at both unit admission and discharge. Complete nutrient intake assessments were performed daily.
Results: Over a median length of stay of 23 days (interquartile range: 15-41 days), 216 (53%) participants gained or lost more than or equal to 2.5% of their body weight. Two hundred eighty-two (70%) participants had recognizable lower extremity pitting edema at admission and/or discharge. The amount of weight change was strongly and positively correlated with multiple indicators of both nutrient intake and the change in the amount of peripheral edema. By multivariable analysis, the strongest predictor of weight change was maximal calf circumference change (partial R (2) = .35, p < .0001), followed by average daily energy intake (partial R (2) = .14, p < .0001), and the interaction of energy intake by time (partial R (2) = .02, p < .0001).
Conclusions: Many older patients either gain or lose a significant amount of weight after admission to a transitional care unit. Because of the apparent high prevalence of co-occurring changes in total body water, the weight changes do not necessarily represent changes in nutritional status. Although repeat calf circumference measurements may provide some indication as to how much of the weight change is due to changes in body water, there is currently no viable alternative to monitoring the nutrient intake of older recuperative care patients in order to ensure that their nutrient needs are being met.
Keywords: Anthropometrics.; Edema; Elderly; Malnutrition; Transitional care; Weight loss.