Proposal for new diagnostic criteria for low skeletal muscle mass based on computed tomography imaging in Asian adults

Abstract Objectives Low skeletal muscle, referred to as sarcopenia, has been shown to be an independent predictor of lower overall survival in various kinds of diseases. Several studies have evaluated the low skeletal muscle mass using computed tomography (CT) imaging. However, the cut-off values based on CT imaging remain undetermined in Asian populations. Methods Preoperative plain CT imaging at the third lumbar vertebrae level was used to measure the psoas muscle mass index (PMI, cm2 /m2 ) in 541 adult donors for living donor liver transplantation (LDLT). We analyzed PMI distribution according to sex or donor age, and determined the sex-specific cut-off values of PMI in order to define low skeletal muscle mass. Results PMI in males was significantly higher than that observed in females (8.85 ± 1.61 cm2 /m2 versus 5.77 ± 1.21 cm2 /m2 ; P < 0.001). PMI was significantly lower in the older (≥ 50 years) versus in younger (< 50 years) donors in both males and females ( P < 0.001, P < 0.001, respectively). On the basis of the younger donor data, we determined the sex-specific cut-off values for the low skeletal muscle mass was 6.36 cm2 /m2 for males and 3.92 cm2 /m2 for females (mean – 2 standard deviations). Conclusion Data from healthy young Asian adults were used to establish new criteria for low skeletal muscle mass that would be applicable for defining sarcopenia in Asian populations.