Optimal Skeletal Muscle Mass Index Cut-Off Values for Presarcopenia Evaluated by Computed Tomography against Dual-Energy X-ray Absorptiometry in Patients with Chronic Liver Disease

Abstract

Although dual-energy X-ray absorptiometry (DXA) and body impedance analysis are commonly used to measure skeletal muscle mass (SMM), a computed tomography (CT) scan is preferred in clinical practice. We aimed to propose the cut-off values of skeletal muscle mass index (SMI) calculated using CT scans, using DXA as the reference method. We retrospectively assessed 589 patients with chronic liver disease. The SMI was assessed using appendicular SMM by DXA and total muscle area at the level of the third lumbar vertebra (L3) calculated by CT. The cut-off value was determined with reference to the Asian Working Group for Sarcopenia criteria. DXA identified 251 (42.6%) patients as having presarcopenia. In men, the cut-off value of SMI for presarcopenia was determined to be 45.471 cm²/m², with an area under the curve (AUC) of 0.863 (95% confidence interval (CI): 0.823 to 0.903), and in women, this value was determined to be 35.170 cm²/m², with an AUC of 0.846 (95% CI: 0.800 to 0.892). Cohen's kappa coefficient was 0.575 (95% CI: 0.485-0.665) in men and 0.539 (95% CI: 0.438-0.639) in women.

Keywords: computed tomography; dual-energy X-ray absorptiometry; sarcopenia; skeletal muscle mass.

Figure 1

Correlations between the SMI and ASMI in (A) men and (B) women. ASMI, appendicular skeletal muscle mass index; SMI, skeletal muscle mass index.

Figure 2

Mean differences of Z-scores (ASMI minus SMI) in (A) men and (B) women. Normality was examined using the Shapiro–Wilk test. ASMI, appendicular skeletal muscle mass index; SMI, skeletal muscle mass index; p, p-value.

Figure 3

Bland–Altman plot of muscle mass z-scores derived from the skeletal muscle mass index and appendicular skeletal muscle mass index. It represents 95% limits of agreement and 95% CIs between muscle mass z-scores derived from ASMI and SMI in (A) men and (B) women. ASMI, appendicular skeletal muscle mass index; SMI, skeletal muscle mass index; MD, mean differences; CI, confidence interval; UL, upper limit; LL, lower limit.

Figure 4

Receiver operating characteristic curves and the cut-off values for (A) men and (B) women. CI, confidence interval.