The potential role of dual-energy X-ray absorptiometry in the assessment of body composition in cirrhotic patients.

Very little information is available on body composition in patients with cirrhosis. Difficulties arise in studying these patients because they tend to retain fluid and this results in changes in tissue density and in the hydration fraction of fat-free mass. As the classic body composition techniques rely on the assumption that these variables remain constant, use of these methods will result in either under- or overestimates of body composition variables. Use of multicomponent models, employing two or more measurement techniques, will obviate the need for some of the assumptions inherent in the use of single techniques, thereby increasing the accuracy of the assessments without loss of precision. Dual-energy x-ray absorptiometry can be used to measure total body bone mineral, fat, and fat-free soft tissue mass. In healthy individuals excellent agreement is observed between data obtained using this technique and data obtained from the more established reference methods. However, the degree to which the absorptiometry measurements of soft tissue are sensitive to the hydration is not known. Thus, in order to assess this method of body composition analysis in patients with chronic liver disease, a multicomponent model must be devised which incorporates the absorptiometry technique and allows cross-validation of the individual component measures.