Concordance between muscle mass assessed by bioelectrical impedance analysis and by dual energy X-ray absorptiometry: a cross-sectional study

Abstract

BackgroundBesides magnetic resonance imaging, dual energy X-ray absorptiometry (DXA) seems the most reliable tool to evaluate body composition and is often considered as the gold standard in clinical practice. Bioelectrical impedance analysis (BIA) could provide a simpler, portative, and less expensive alternative. Because the body composition assessment by BIA is device-dependent, the aim of this study was to appraise the concordance between the specific bioelectrical impedance device InBody S10 and DXA for the body composition evaluation.MethodsBody composition, included appendicular lean mass divided by height squared (ALM/ht2) was measured by DXA (Hologic QDR Discovery device) and by BIA (InBody S10 Biospace device). Agreement between tools was assessed by means of the Bland Altman method and reliability was determined using the IntraClass Coefficient (ICC). ICC was also computed to assess the reliability of the test-retest performed by the same operator or by two different ones.ResultsA total of 219 subjects were enrolled in this study (mean age: 43.7 ± 19.1 years old, 51.6% of women). For the ALM/ht2, reliability of the test-retest of the BIA was high with an ICC of 0.89 (95%CI: 0.86-0.92) when performed by the same operator and an ICC of 0.77 (95%CI: 0.72-0.82) when performed by two different operators. Agreement between ALM/ht2 assessed by DXA and BIA was low (ICC = 0.37 (95%CI: 0.25-0.48)). Mean ALM/ht2 was 9.19 ± 1.39 kg/m2 with BIA and 7.34 ± 1.34 kg/m2 with DXA, (p < 0001). A formula developed using a multiple regression analysis, and taking into account muscle mass assessed by BIA, as well as sex and body mass index, explains 89% of the ALM/ht2 assessed by DXA.ConclusionsAlthough our results show that the measure of ALM/ht2 by BIA is reliable, the agreement between DXA and BIA is low. Indeed, BIA seems to overestimate ALM/ht2 compared to DXA and, consequently, it is important to use an adapted formula to obtain measurement of the appendicular lean mass by BIA close to that measured by DXA.

The Authors reply: “Dual energy X‐ray absorptiometry: gold standard for muscle mass?” by Scafoglieri et al.

“…As fat is a term used in many different contexts, perhaps a different name should have been given to what is now known as DXA fat mass. We agree that DXA lean body mass is smaller than FFM . FFM is the mass of the body excluding the chemical fat.…”

Effects of in‐hospital exercise on sarcopenia in hepatoma patients who underwent transcatheter arterial chemoembolization

“…Thus, this discrepancy may be explained by the methodological differences in evaluation of SMI. BIA is useful for assessment of skeletal muscle mass; however, the major limitation of these methods is an inability to differentiate water from muscle. Therefore, edematous tissue can falsely elevate muscle mass readings .…”

A cross-sectional study on sarcopenia using different methods: reference values for healthy Saudi young men

“…For example, Inbody S10 demonstrated systematic overestimation of muscle mass compared to DXA [25], and the agreement of ALM/ht 2 assessed by Inbody S10 (9.19 ± 1.39 kg/m 2 ) and DXA (7.34 ± 1.34 kg/m 2 ) was low (ICC = 0.37, P  < 0.001) [26]. The portable Inbody 230 is acceptable for estimation of FM and FFM, particularly for healthy men, but it is not appropriate to estimate appendicular FFM, and must be reevaluated by the manufacturer before it can be used for the measurement of sarcopenia [27].…”