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

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 reliability of the DF-BIA device.

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.

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 linear equation (R² = 0.93).

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 interchangeable for the assessment of muscle mass.