mp-194 - Medical Policies - Alabama
Whole Body Dual X-Ray Absorptiometry (DEXA) to Determine Body Composition
Policy Number: MP-194
Latest Review Date: September 2021
Policy Grade: A
Dual x-ray absorptiometry (DXA) body composition studies is considered investigational.
DESCRIPTION OF PROCEDURE OR SERVICE:
Using low dose x-rays of two different energy levels, whole body dual x-ray absorptiometry (DXA) measures lean tissue mass and total and regional body fat as well as bone density. DXA scans have become a tool for research on body composition e.g. as a more convenient replacement for underwater weighing. This review addresses potential applications in clinical care rather than research use of the technology.
Body Composition Measurement
Body composition measurements can be used to quantify and assess the relative proportions of
specific body compartments such as fat and lean mass (e.g., bones, tissues, organs, muscles). These measurements may be more useful in informing diagnosis, prognosis, or therapy than standard assessments (e.g., body weight, body mass index) that do not identify the contributions of individual body compartments or their particular relationships with health and disease. While these body composition measurements have been most frequently utilized for research purposes, they may be useful in clinical settings to:
- Evaluate the health status of undernourished patients, those impacted by certain disease states (e.g., anorexia nervosa, cachexia), or those undergoing certain treatments (eg, antiretroviral therapy, bariatric surgery).
- Evaluate the risk of heart disease or diabetes by measuring visceral fat vs total body fat.
- Assess body composition changes related to growth and development (e.g., infancy, childhood), aging (e.g., sarcopenia), and in certain disease states (eg, HIV, diabetes).
- Evaluate patients in situations where body mass index is suspected to be discordant with total fat mass (e.g., body-building, edema).
A variety of techniques have been researched, including most commonly, anthropomorphic measures, bioelectrical impedance, and dual X-ray absorptiometry (DXA). All of these techniques are based in part on assumptions regarding the distribution of different body compartments and their density, and all rely on formulas to convert the measured parameter into an estimate of body composition. Therefore, all techniques will introduce variation based how the underlying assumptions and formulas apply to different populations of subjects, (i.e., different age groups, ethnicities, or underlying conditions). Techniques using anthropomorphics, bioelectrical impedance, underwater weighing, and DXA are briefly reviewed as followed.
Anthropomorphic techniques for the estimation of body composition include measurements of skin-fold thickness at various sites, bone dimensions, and limb circumference. These measurements are used in various equations to predict body density and body fat. Due to its ease of use, a measurement of skin-fold thickness is one of the most commonly used techniques. The technique is based on the assumption that the subcutaneous adipose layer reflects total body fat, but this association may vary with age and gender.
Bioelectrical impedance is based on the relationship between the volume of the conductor (i.e., the human body), the conductor’s length (i.e., height), the components of the conductor (i.e., fat and fat-free mass), and its impedance. Estimates of body composition are based on the assumption that the overall conductivity of the human body is closely related to lean tissue. The impedance value is then combined with anthropomorphic data to give body compartment measures. The technique involves attaching surface electrodes to various locations on the arm and foot. Alternatively, the patient can stand on pad electrodes.
Underwater weighing requires the use of a specially constructed tank in which the subject is seated on a suspended chair. The subject is then submerged in the water while exhaling. While valued as a research tool, weighing people underwater is obviously not suitable for routine clinical use. This technique is based on the assumption that the body can be divided into two compartments with constant densities: adipose tissue with a density of 0.9gm/cm3 and lean body mass (i.e., muscle and bone) with a density of 1.1 g/cm3. One limitation of the underlying assumption is the variability in density between muscle and bone; for example, bone has a higher density than muscle, and bone mineral density varies with age and other conditions. Also, the density of body fat may vary, depending on the relative components of its constituents, (e.g., glycerides, sterols, and glycolipids).
Dual X-Ray Absorptiometry (DXA)
While the cited techniques assume 2 body compartments, DXA can estimate three body compartments consisting of fat mass, lean body mass, and bone mass. DXA systems use a source that generates x-rays at two energies. The differential attenuation of the two energies is used to estimate the bone mineral content and the soft tissue composition. When two x-ray energies are used, only two tissue compartments can be measured; therefore, soft tissue measurements (i.e., fat and lean body mass) can only be measured in areas in which no bone is present. DXA also has the ability to determine body composition in defined regions, i.e., in the arms, legs, and trunk. DXA 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% to 85% and can be variable in certain disease states. Other assumptions used to derive body composition estimates are considered proprietary by DXA manufacturers.
The most recent literature review was updated through July 23, 2021.
Summary of Evidence
For individuals who have a clinical condition associated with abnormal body composition who receive DXA body composition studies, the evidence includes systematic reviews and several cross-sectional studies comparing DXA with other techniques. Relevant outcomes are symptoms and change in disease status. The available studies are primarily conducted in research settings and often use DXA body composition studies as a reference standard; these studies do not permit conclusions about the accuracy of DXA for measuring body composition. A systematic review exploring the clinical validity of DXA measurements aginst reference methods for the quantification of intra-abdominal adipose tissue raised concerns for precision and reliability. More importantly, no studies were identified in which DXA body composition measurements were actively used in patient management. The evidence is insufficient to determine the effects of the technology on health outcomes.
For individuals who have a clinical condition managed by monitoring changes in body composition over time who receive serial DXA body composition studies, the evidence includes several prospective studies monitoring patients over time. Relevant outcomes are symptoms and change in disease status. The studies used DXA as a tool to measure body composition and were not designed to assess the accuracy of DXA. None of the studies used DXA findings to make patient management decisions or addressed how serial body composition assessment might improve health outcomes. The evidence is insufficient to determine the effects of the technology on health outcomes.
Practice Guidelines and Position Statements
American College of Radiology et al
The American College of Radiology (ACR), the Society for Pediatric Radiology (SPR), and the Society of Skeletal Radiology (SRR) (2018) issued a collaborative practice parameter to assist practitioners in providing appropriate radiologic care for their patients. DXA was described as a "clinically proven, accurate and reproducible method of measuring bone mineral density (BMD) in the lumbar spine, proximal femur, forearm, and whole body," that "may also be used to measure whole-body composition, including nonbone lean mass (LM) and fat mass (FM)." DXA measurement of BMD, LM, or FM is indicated whenever a clinical decision is likely to be directly influenced by the test result. In particular, LM and FM may be useful in assessing conditions such as sarcopenia and cachexia. Specifically, DXA may be indicated as a tool for the measurement of regional and whole body FM and LM in patients afflicted with conditions such as malabsorption, cancer, or eating disorders.
The International Society for Clinical Densitometry
The International Society for Clinical Densitometry (2015) updated its statements on the use of dual x-ray absorptiometry (DXA) for body composition. The following statements were made on the use of DXA total body composition with regional analysis:
- To assess fat distribution in patients with HIV who are using antiretroviral agents known to increase the risk of lipoatrophy.
- To assess fat and lean mass changes in obese patients undergoing bariatric surgery (or medical, diet, or weight loss regimens with anticipated large weight loss) when weight loss exceeds approximately 10%. The statement noted that the impact of DXA studies on clinical outcomes in these patients is uncertain.
- To assess fat and lean mass in patients with muscle weakness and poor physical functioning. The impact on clinical outcomes is uncertain.
Of note, pregnancy is a contraindication to use of DXA to measure body composition. The statement also adds that the clinical utility of DXA measurements of adiposity and lean mass (e.g., visceral adipose tissue, lean mass index, fat mass index) is uncertain. Furthermore, while the use of DXA adiposity measures such as fat mass index may be useful in risk-stratifying patients for cardio-metabolic outcomes, specific thresholds to define obesity have not been established.
International Conference on Sarcopenia and Frailty Research Task Force
Evidence-based clinical practice guidelines for the screening, diagnosis, and management of sarcopenia were developed by the International Conference on Sarcopenia and Frailty Research (ICSFR) task force in 2018. The following recommendations were made:
- Screening for sarcopenia can be performed using gait speed analysis or SARC-F questionnaire.
- Individuals screened as positive for sarcopenia should be referred for further assessment to confirm the presence of the
- DXA imaging should be used to determine low levels of lean body mass when diagnosing sarcopenia.
The recommendation regarding the diagnostic use of DXA received a conditional (weak) recommendation. The certainty of the evidence for DXA assessment was ranked low due to:
- DXA studies featuring populations from low-middle income countries are lacking.
- DXA measurement of lean body mass rather than muscle mass may potentially misclassify body composition in certain individuals.
- Incorporation of DXA measurements of lean body mass may have limited additional benefit for the prediction of relevant health outcomes (eg, falls, fractures, lowered physical performance, mobility).
U.S. Preventive Services Task Force Recommendations
No U.S. Preventive Services Task Force recommendations for whole body DXA have been identified
Dual X-ray absorptiometry (DXA), body composition assessment, anthropomorphic techniques, skin-fold thickness, body composition, DXA, Total Body DXA scan
APPROVED BY GOVERNING BODIES:
Body composition software for several bone densitometer systems have been approved by the U.S. Food and Drug Administration through premarket approval process. This includes Lunar iDXA systems (GE Healthcare, Madison, WI), Hologic DXA systems (Hologic, Bedford MA), and Norland DXA systems (Norland Corp., Fort Atkinson, WI).
Coverage is subject to member’s specific benefits. Group specific policy will supersede this policy when applicable.
ITS: Home Policy provisions apply
FEP contracts: Special benefit consideration may apply. Refer to member’s benefit plan. FEP does not consider investigational if FDA approved and will be reviewed for medical necessity.
Unlisted diagnostic radiographic procedure
- Alves FD, Souza GC, Biolo A, et al. Comparison of two bioelectrical impedance devices and dual-energy X-ray absorptiometry to evaluate body composition in heart failure. J Hum Nutr Diet. Dec 2014;27(6):632-638.
- Alves Junior CAS, de Lima LRA, de Souza MC et al. Anthropometric measures associated with fat mass estimation in children and adolescents with HIV. Appl Physiol Nutr Metab, 2018 Oct 5;44(5).
- American College of Radiology. ACR-SPR-SSR Practice Parameter for the Performance of Dual-energy X-ray Absorptiometry (DXA). 2018; https://www.acr.org//media/ACR/Files/Practice-Parameters/DXA.pdf.
- Arthur RS, Xue X, Kamensky V, et al. The association between DXA-derived body fat measures and breast cancer risk among postmenopausal women in the Women's Health Initiative. Cancer Med. Feb 2020; 9(4): 1581-1599.
- Bazzocchi A, Ponti F, Cariani S, et al. Visceral fat and body composition changes in a female population after RYGBP: a two-year follow-up by DXA. Obes Surg. Mar 2015;25(3):443-451.
- Bedogni G, Agosti F, De Col A, et al. Comparison of dual-energy X-ray absorptiometry, air displacement plethysmography and bioelectrical impedance analysis for the assessment of body composition in morbidly obese women. Eur J Clin Nutr. Nov 2013; 67 (11):1129-1132.
- Bundred J, Kamarajah SK, Roberts KJ. Body composition assessment and sarcopenia in patients with pancreatic cancer: a systematic review and meta-analysis. HPB (Oxford), 2019 May 27.
- Calella P, Valerio G, Brodlie M et al. Tools and Methods Used for the Assessment of Body Composition in Patients With Cystic Fibrosis: A Systematic Review. Nutr Clin Pract, 2019 Feb 7.
- Calella P, Valerio G, Brodlie M et al. Cystic fibrosis, body composition, and health outcomes: a systematic review. Nutrition, 2018 Nov;55-56:131-139.
- Dent E, Morley JE, Cruz-Jentoft AJ et al. International Clinical Practice Guidelines for Sarcopenia (ICFSR): Screening, Diagnosis and Management. J Nutr Health Aging, 2018 Dec 1;22(10).
- Dordevic AL, Bonham M, Ghasem-Zadeh A et al. Reliability of Compartmental Body Composition Measures in Weight-Stable Adults Using GE iDXA: Implications for Research and Practice. Nutrients, 2018 Oct 12;10(10).
- Elkan AC, Engvall IL, Tengstrand B et al. Malnutrition in women with rheumatoid arthritis is not revealed by clinical antrhopometrical measurements or nutritional evaluation tools. Eur J Clin Nutr 2008; 62(10):1239-1247.
- Franzoni E, Ciccarese F, Di Pietro E, et al. Follow-up of bone mineral density and body composition in adolescents with restrictive anorexia nervosa: role of dual-energy X-ray absorptiometry. Eur J Clin Nutr. Feb 2014; 68 (2):247-252.
- International Society for Clinical Densitometry. 2015 ISCD Official Positions – Adult. 2015; https://www.iscd.org/official-positions/2015-iscd-official-positions-adult/.
- Iyengar NM, Arthur R, Manson JE et al. Association of Body Fat and Risk of Breast Cancer in Postmenopausal Women With Normal Body Mass Index: A Secondary Analysis of a Randomized Clinical Trial and Observational Study. JAMA Oncol, 2019 Feb;5(2):155-163.
- Jensky-Squires NE, Dieli-Conwright CM, Rossuello A et al. Validity and reliability of body composition analysers in children and adults. Br J Nutr 2008;100(4):859-865.
- Kullberg J, Brandberg J, Angelhed JE et al. Whole-body adipose tissue analysis: comparison of MRI, CT and dual energy x-ray absorptiometry. Br J Radiol 2009; 82(974):123-130.
- Liem ET, De Lucia Rolfe E, L’Abee C et al. Measuring abdominal adiposity in 6 to 7 year old children. Eur J Clin Nutr 2009; 63(7):835-841.
- Lindqvist C, Brismar TB, Majeed A et al. Assessment of muscle mass depletion in chronic liver disease: Dual-energy x-ray absorptiometry compared with computed tomography. Nutrition, 2019 Feb 1;61:93-98.
- Monteiro PA, Antunes Bde M, Silveira LS, et al. Body composition variables as predictors of NAFLD by ultrasound in obese children and adolescents. BMC Pediatr. 2014; 14: 25.
- Murphy J, Bacon SL, Morais JA et al. Intra-Abdominal Adipose Tissue Quantification by Alternative Versus Reference Methods: A Systematic Review and Meta-Analysis. Obesity (Silver Spring), 2019 Jul;27(7).
- Reina D, Gómez-Vaquero C, Díaz-Torné C et al. Assessment of nutritional status by dual X-Ray absorptiometry in women with rheumatoid arthritis: A case-control study. Medicine (Baltimore), 2019 Feb;98(6):e14361.
- Sheean P, Gonzalez MC, Prado CM et al. American Society for Parenteral and Enteral Nutrition Clinical Guidelines: The Validity of Body Composition Assessment in Clinical Populations. JPEN J Parenter Enteral Nutr, 2019 Jun 20.
- Sinclair M, Hoermann R, Peterson A et al. Use of Dual X-ray Absorptiometry in men with advanced cirrhosis to predict sarcopenia-associated mortality risk. Liver Int., 2019 Feb 13;39(6).
- Staunstrup LM, Nielsen HB, Pedersen BK, et al. Cancer risk in relation to body fat distribution, evaluated by DXA-scans, in postmenopausal women - the Prospective Epidemiological Risk Factor (PERF) study. Sci Rep. Mar 29 2019; 9(1): 5379.
- Tompuri TT, Lakka TA, Hakulinen M, et al. Assessment of body composition by dual-energy X-ray absorptiometry, bioimpedance analysis and anthropometrics in children: the Physical Activity and Nutrition in Children Study. Clin Physiol Funct Imaging. Jan 2015; 35(1):21-33.
- Woolcott OO, Bergman RN. Defining cutoffs to diagnose obesity using the relative fat mass (RFM): Association with mortality in NHANES 1999-2014. Int J Obes (Lond). Jun 2020; 44(6): 1301-1310.
- Ziai S, Coriati A, Chabot K, et al. Agreement of bioelectric impedance analysis and dual-energy X-ray absorptiometry for body composition evaluation in adults with cystic fibrosis. J Cyst Fibros. Sep 2014; 13(5):585-588.
Medical Policy Group, August 2004 (4)
Medical Policy Administration Committee, August 2004
Available for comment August 24-October 7, 2004
Medical Policy Group, August 2006 (1)
Medical Policy Group, January 2007 (2)
Medical Policy Group, January 2009 (1)
Medical Policy Panel, February 2010
Medical Policy Group, June 2010 (2)
Medical Policy Group, June 2011; Added Key Word
Medical Policy Group, July 2011; Updated Key Points and References
Medical Policy Group, February 2012 (2): 2012 Update-Key Points & References
Medical Policy Group, January 2013 (2): 2013 Update to Key Points & References; policy statement remains unchanged
Medical Policy Panel, December 2014
Medical Policy Group, December 2014 (4): Update to Key Points, Approved Governing Bodies, and References. No change in policy statement.
Medical Policy Panel, December 2015
Medical Policy Group, December 2015 (2): 2015 Updates to Description, Key Points, and References; no change in policy statement.
Medical Policy Panel, September 2017
Medical Policy Group, September 2017 (7): Updates to Description, Key Points, and References. Removed Previous Coding section (0028T deleted effective Jan 2009). No change in policy statement.
Medical Policy Panel, September 2018
Medical Policy Group, October 2018 (7): Updates to Key Points and References. No change in policy statement.
Medical Policy Panel, September 2019
Medical Policy Group, September 2019 (7): Updates to Key Points and References. No change in policy statement.
Medical Policy Panel, September 2020
Medical Policy Group, September 2020 (7): Updates to Description, Key Points and References. No change in policy statement.
Medical Policy Panel, September 2021
Medical Policy Group, September 2021 (7): Literature review completed. Minor updates to Key Points. No new references added. Removed “not medically necessary” statement from Policy Statement. No change in intent.
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