Dual-Frequency Bioelectrical Impedance Analysis is Accurate and Reliable to Determine Lean Muscle Mass in The Elderly

Background: Dual-frequency bioelectrical impedance analysis (DF-BIA) devices are more accessible and affordable than dual-energy X-ray absorptiometry (DXA); however, no studies have reported the accuracy of DF-BIA in body composition measurement, especially in the Thai elderly. The aims of this study were to (1) compare the accuracies of lean muscle masses measured by DF-BIA devices and DXA and (2) assess the reli-ability of the DF-BIA device. Methods: This cross-sectional study was conducted on participants older than 60 years who visited the Orthopedic Clinic of Siriraj Hospital. Whole-body and appendicular skeletal muscle masses (ASMs) were measured using DF-BIA (Tanita RD-545), with DXA (GE Lunar iDXA) as the standard reference. The test-retest reliability of the DF-BIA and the agreement between the devices were assessed using the intraclass correlation coefficient (ICC) and Bland -Altman plots. Regression analysis was used to develop an equation to estimate ASM values from BIA close to those from DXA. Results : The mean age of 88 participants was 73.8 (SD 8.0) years, with women predominating (84.1%). The agreement of BIA and DXA was very high for whole-body lean mass (ICC = 0.954) and ASM (ICC = 0.954), but the mean difference in muscle mass from DF-BIA was overestimated. The ICCs of test-retest reliability for whole-body muscle mass and ASM were 0.987 and 0.988, respectively. The equation for corrected ASM was formulated from a lin-ear equation (R2 = 0.93). Conclusions: Although lean muscle mass from DF-BIA was minimally overestimated relative to DXA, this device had high accuracy and reliability for lean muscle mass evaluation in the elderly. DXA and DF-BIA are for the assessment of muscle mass.