Method for estimating body weight in persons with lower-limb amputation and its implication for their nutritional assessment

Background: Body weight is a good indicator of a person's size and is widely used in clinical assessment. However, health-status assessment based on observed body weight (W-O) is incorrect for persons with limb amputation. Objectives: The objectives were 1) to develop a more accurate and generalized method for estimating body weight in persons with limb amputation, 2) to determine whether corrected body weight can be used to assess nutritional status in persons with limb amputation, and 3) to test the validity of the estimation by using empirical data. Design: Anthropometric data were collected from men from Calcutta and adjoining areas with unilateral lower-extremity amputation (n = 102). Mathematic formulas were developed for determining estimated body weight (W-E) and body mass index (BMI) calculated from both W-O and W-E (ie, BMIO and BMIE, respectively). We assessed nutritional status by using BMIO and BMIE and tested the validity of each by considering the result of nutritional assessment from midupper arm circumference as the gold standard. We also compared the nutritional status results for the subjects with limb amputation with those for a similar sample size of healthy control subjects. Results: BMIE had a stronger association with midupper arm circumference and a higher efficiency (ie, proportion of correct results given by any test method) than did BMIO. Moreover, the results obtained with BMIE were similar to those obtained with BMI in healthy control subjects. However, the nutritional assessments made with BMIO and BMIE did not differ significantly from one another. Conclusion: For persons with limb amputation, W-E provides a better basis for appropriate nutritional evaluation than does W-O.