DESCRIPTION
Measurements of body composition have been used to study how lean body mass and body fat change during health and disease. This has provided a research tool to study the metabolic effects of aging, obesity and various wasting conditions such as occurs with acquired immune deficiency syndrome (AIDS) or post-bariatric surgery. DEXA is based in part on assumptions regarding the distribution of different body compartments and their density, and relies on formulas to convert the measured parameter into an estimate of body composition. This technique also introduces variation based on how the underlying assumptions and formulas apply to different populations of subjects such as different age groups, ethnicities, or underlying conditions.
DEXA can estimate 3 body compartments consisting of fat mass, lean body mass, and bone mass. DEXA systems use a source that generates x-rays at 2 energies. The differential attenuation of the 2 energies is used to estimate the bone mineral content and the soft tissue composition. When 2 x-ray energies are used, only 2 tissue compartments can be measured; therefore, soft tissue measurements (i.e., fat and lean body mass) can only be measured in areas where no bone is present. DEXA also has the ability to determine body composition in defined regions such as the arms, legs, and trunk. DEXA measurements are based in part on the assumption that the hydration of fat-free mass remains constant at 73%. Hydration, however, can vary from 67%–85%, and can be variable in certain disease states. Other assumptions used to derive body composition estimates are considered proprietary by DEXA manufacturers (i.e., Lunar, Hologic, and Norland.)
POLICY
Whole body dual x-ray absorptiometry (DEXA) to determine body composition is considered investigational.
IMPORTANT REMINDER
We develop Medical Policies to provide guidance to Members and Providers. This Medical Policy relates only to the services or supplies described in it. The existence of a Medical Policy is not an authorization, certification, explanation of benefits or a contract for the service (or supply) that is referenced in the Medical Policy. For a determination of the benefits that a Member is entitled to receive under his or her health plan, the Member's health plan must be reviewed. If there is a conflict between the Medical Policy and a health plan, the express terms of the health plan will govern.
ADDITIONAL INFORMATION
Well-designed studies with long-term follow-up published in peer-reviewed journals regarding the use of whole body dual x-ray absorptiometry (DEXA) to determine body composition are not available. It is not known if this technology improves net health outcomes related to patient management or predicting health risks. Also, outcomes with this technology compared with simpler techniques of body composition assessment (i.e., skin-fold thickness, waist-to-hip ratios) are not known.
SOURCES
BlueCross BlueShield Association. Medical Policy Reference Manual. (3:2011). Whole body dual x-ray absorptiometry (DEXA) to determine body composition (6.01.40). Retrieved January 6, 2012 from BlueWeb. (21 articles and/or guidelines reviewed)
Jensky-Squires, N. E., Dieli-Conwright, C. M., Rossuello, A., Erceg, D. N., McCauley, S., & Schroeder, E. T. (2008). Validity and reliability of body composition analysers in children and adults. The British Journal of Nutrition, 100 (4), 859-865. (Level 3 Evidence - Industry sponsored)
Kullberg, J., Brandberg, J., Angelhed, J. E., Frimmel, H., Bergelin, E., Stid, L., et al. (2009). Whole-body adipose tissue analysis: Comparison of MRI, CT and dual energy X-ray absorptiometry. The British Journal of Radiology, 82 (974), 123-130.
LaForgia, J., Dollman, J., Dale, M. J., Withers, R. T., & Hill, A. M. (2009). Validation of DXA body composition estimates in obese men and women. Obesity, 17 (4), 821-826.
Liem, E. T., De Lucia Rolfe, E., L'Abée, C., Sauer, P. J., Ong, K. K., & Stolk, R. P. (2009). Measuring abdominal adiposity in 6 to 7-year-old children. European Journal of Clinical Nutrition, 63 (7), 835-841.
Provyn, S., Clarvs, J. P., Wallace, J., Scafoglieri, A., & Reilly, T. (2008). Quality control, accuracy, and prediction capacity of dual energy X-ray absorptiometry variables and data acquisition. Journal of Physiological Anthropology, 27 (6), 317-323.
Sun, Q., van Dam, R. M., Spiegelman, D., Hevmsfield, S. B., Willet, W. C., & Hu, F. B. Comparison of dual-energy x-ray absorptiometric and anthropometric measures of adiposity in relation to adiposity-related biologic factors. American Journal of Epidemiology, 172 (12), 1442-1454.
U. S. Food and Drug Administration. (2007, June). Center for Devices and Radiological Health. 510(k) Premarket Notification Database. K071570. Retrieved January 9, 2012 from http://www.accessdata.fda.gov/cdrh_docs/pdf7/K071570.pdf.
ORIGINAL EFFECTIVE DATE: 8/14/2010
MOST RECENT REVIEW DATE: 2/9/2012
ID_BA
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