Feasibility of Using Fat Degeneration of Lumbar Extensor Muscle as an Alternative Diagnostic Criterion for Sarcopenia in Patients with Osteoporotic Vertebral Fractures.

Feasibility study.To investigate the feasibility of using fat degeneration of lumbar extensor muscle (LEM) as an alternative diagnostic criterion for sarcopenia in patients with osteoporotic vertebral fractures.Although sarcopenia has been gaining increased attention among researchers and healthcare practitioners, there is uncertainty about the association between sarcopenia and fat degeneration of LEM.In this study, 33 patients with osteoporotic vertebral fractures (group 1) and 29 patients without such fractures (group 2) were enrolled. Sarcopenia was diagnosed in accordance with the Asian Working Group for Sarcopenia (AWGS) criteria, including assessment of extremity muscle mass using dual-energy X-ray absorptiometry, grip strength, and gait speed. The bone mineral density and fat degeneration of LEM were investigated using magnetic resonance imaging.The mean rates of fat degeneration of LEM and the skeletal muscle index were 38.3% and 5.5 kg/m2 in group 1 and 28.9% and 6.3 kg/m2 in group 2, respectively. The fat degeneration of LEM was negatively correlated with gait speed (r=-0.44, p=0.01) and handgrip strength (r=-0.37, p=0.01). The fat degeneration of LEM also demonstrated a significant relationship with osteoporotic vertebral fractures (p=0.01). Receiver operating characteristic curve analysis between fat degeneration of LEM and osteoporotic vertebral fractures showed that the cut-off value of fat degeneration was 31.9% (sensitivity=0.67, specificity=0.66). There was a positive correlation between sarcopenia defined by the AWGS and that defined by the 31.90% cut-off value of fat degeneration of LEM instead of extremity muscle mass (r=0.46, p=0.01).These results suggest the feasibility of using fat degeneration of LEM as an alternative diagnostic criterion for sarcopenia in patients with osteoporotic vertebral fractures. A cut-off value of fat degeneration of LEM of 31.9% was shown to be useful for diagnosing osteoporotic vertebral fractures.