Dual-Energy X-ray Absorptiometry and Bioelectrical Impedance Analysis are Beneficial Tools for Measuring the Trunk Muscle Mass of Patients with Low Back Pain

Introduction: Limb muscle mass measurement using dual-energy X-ray absorptiometry (DXA) is considered the gold standard for the diagnosis of sarcopenia. Moreover, bioelectrical impedance analysis (BIA) is also recognized as a beneficial tool considering its high correlation with DXA. However, it remains to be elucidated whether DXA and BIA can accurately measure trunk lean mass. The aim of this study was to investigate the correlation between DXA and BIA measurements of trunk muscle mass and the cross-sectional area (CSA) of trunk muscles measured using magnetic resonance imaging (MRI) and to compare measures of trunk muscle mass obtained using DXA and BIA in patients with low back pain (LBP). Methods: In total, 65 patients participated in the study. The correlation between DXA and BIA measurements and the CSA of trunk and paraspinal muscles at the L4-5 level were calculated. In addition, the correlation between DXA and BIA measurements of trunk muscle mass and the differences between these two measurements were determined. Results: The correlation coefficient between DXA and BIA trunk muscle mass measurement and trunk muscle CSA was 0.74 and 0.56 for men and 0.69 and 0.44 for women, respectively. DXA and BIA measurement values showed a significantly moderate correlation with the CSA of the erector spinae (ES) and psoas major (PM). The multifidus (MF) CSA did not correlate with measurements of DXA and BIA in both men and women. Although DXA and BIA measurements were significantly correlated, a significant difference between these two measurements was found. BIA overestimated the trunk muscle mass significantly compared with DXA. Conclusions: Trunk muscle mass measured with DXA and BIA was correlated with the CSA of most trunk muscles. Although the measurement of DXA and BIA showed a high correlation, BIA overestimated trunk muscle mass compared with DXA. Both DXA and BIA are beneficial for measuring trunk muscle mass.