Comparison of Bioelectrical Impedance Analysis and Dual-energy X-ray Absorptiometry for the Diagnosis of Sarcopenia in the Older Adults with Metabolic Syndrome: Equipment-specific Equation Development

Objective: Metabolic syndrome (MetS) and sarcopenia together pose significant health risks, increasing frailty, falls, and fractures in older adults. This study compared muscle mass measurements obtained using two different dual-energy X-ray absorptiometry (DXA) machines and bioelectrical impedance analysis (BIA), and evaluated the accuracy of these measurements in these older adults.

Methods: In this prospective multicenter cohort study, patients aged ≥ 65 years with MetS had their muscle mass assessed using both BIA and DXA. Two DXA devices, Hologic Horizon and GE Lunar Prodigy, were used as clinical standards for sarcopenia diagnosis. Statistical analyses generated equations for transforming BIA results to match those from DXA, enhancing comparability.

Results: Participants had a mean age of 73.2 ± 5.3 years. The mean appendicular skeletal muscle mass (ASM) measured by BIA and DXA was 19.7 ± 3.1 kg (BIA) and 18.1 ± 2.9 kg (DXA) for males, and 13.7 ± 2.2 kg (BIA) and 12.6 ± 1.8 kg (DXA) for females. Device-specific equations were developed to estimate DXA-measured ASM based on BIA results. These equations are presented for all participants and for each DXA device, highlighting significant differences in prediction models between the two DXA machines.

Conclusion: The study developed device-specific equations for sarcopenia diagnosis in older adults with MetS, highlighting substantial differences between Hologic and GE Lunar devices. While BIA may offer a more accessible alternative to DXA, the variation in prediction formulas underscores the need for standardized equipment to ensure consistency in sarcopenia diagnosis.