BODY-COMPOSITION AT THE BEDSIDE

Objective :To evaluate the use of an inexpensive hand-held bioelectric impedance analysis machine which measures lean body mass, by technica l comparisons against standard instruments and techniques (an in-house bioelectric impedance machine and dual energy X-ray absorptiometry), and by performing body composition analyses in groups oi potentially m alnourished patients. Design: Prospective simultaneous comparison oi m easurements made by the hand-held and in-house bioelectric analysis ma chines and dual energy x-ray absorptiometry. Setting: Medical Physics Department and Gastrointestinal Unit in a university teaching hospital . Subjects/methods: One hundred and sixty subjects were recruited into the study. Data from 58 adolescent and 14 adult volunteers and from 4 2 adult patients were used for technical comparisons (n=114). Body com position information was evaluated (n=102) for 60 adult volunteers and 42 patients (17 with eating disorders, 7 with chronic alcoholic pancr eatitis and 18 with inflammatory bowel disease). Outcome measures: Est imation of bias, limits of agreement and correlations on data from the three machines. Relationships between percentage body mass as lean, a bsolute weights and body mass index, in the adult subjects. Results: B oth resistance and calculated impedance measured by the hand-held mach ine significantly correlated with the impedance measured by the in-hou se machine (r=0.996; P<0.0001). An estimation of the level of agreemen t in percentage lean measurement between dual energy x-ray absorptiome try and hand-held bioelectrical impedance analysis machine by the Blan d and Altman method showed a bias of -0.07% and satisfactory limits of agreement from -7.97% to 7.76%. Body mass index was similar in the gr oups oi healthy men and women, but proportion of weight as lean was si gnificantly higher in men than women. In underweight patients with eat ing disorders, the ratio of lean to fat varied widely; in inflammatory bower disease patients, proportions of lean and fat were similar to c ontrols; however patients with alcoholic pancreatitis had values for b ody mass index similar to controls, but had significantly lower propor tion of their body weight as lean (P<0.05). Conclusion: In non-obese a nd thin adults, an accurate two-compartment (lean, fat) measurement of body composition can be made in 10 min by using an inexpensive, hand- held, bioelectric impedance analysis machine.