Simple Age Specific Cutoff Value for Sarcopenia Evaluated by Computed Tomography.

OBJECTIVE: Until now, cutoff values of low skeletal muscle mass using computed tomography (CT) were driven by optimal stratification to predict mortality in cancer patients. The aim of the present study was to investigate the simple, age-specific, cutoff value of low skeletal muscle mass by CT in healthy adults.

DESIGN: This is a retrospective, observational, single-center study.

SETTING: This study was performed in the health screening department of a university-affiliated hospital during a 10-year period.

PATIENTS: Medical records of 1,422 patients presenting to the health screening department were reviewed. Cross-sectional area of psoas muscle at the level of the third lumbar vertebra on abdominal CT was measured and adjusted by height (mm2/m2). This value (psoas muscle index [PMI]) was assumed to represent whole skeletal muscle mass. We divided the patients according to age, sex, and defined cutoff value of low skeletal muscle mass as 2 SDs below the mean.

INTERVENTION: None.

MEASUREMENTS AND MAIN RESULTS: Among 1,422 patients, 550 patients (38.6%) were male. The mean PMI was 896.60 (mm2/m2) for men and 570.54 (mm2/m2) for women. Cutoff values of PMI for men were 592.3 mm2/m2 for 20-39 years, 474.0 mm2/m2 for 40-49 years, 422.2 mm2/m2 for 50-59 years, 374.4 mm2/m2 for 60-69 years, and 331.5 mm2/m2 for 70-89 years. The values for women were 399.9 mm2/m2 for 20-39 years, 287.7 mm2/m2 for 40-49 years, 242.5 mm2/m2 for 50-59 years, 220.4 mm2/m2 for 60-69 years, and 147.6 mm2/m2 for 70-89 years.

CONCLUSIONS: Cutoff values of low skeletal muscle mass using CT differed in healthy adults as age increased. Further studies on the effect of sarcopenia intervention using this cutoff value are needed.