Diagnostic value of different skeleton muscles in elderly COPD patients with sarcopenia

The purpose of this study was to explore the value of different skeletal muscles in assessing muscle mass in elderly chronic obstructive pulmonary disease (COPD) patients with sarcopenia.

A cross-sectional analysis was conducted on a sample of elderly COPD patients with and without sarcopenia. Muscle mass measurements, including body mass index (BMI), weight, skeletal muscle index (SMI), 6-m walk test (6MWT), five-repetition sit-to-stand test (5STS), grip strength, calf circumference (CC), rectus abdominis thickness (RAT), rectus femoris cross-sectional area (RF-CSA), quadriceps femoris muscle thickness (QFMT), L1 muscle cross-sectional area (L1M CSA), and pectoralis muscle cross-sectional area (PM CSA). Statistical analyses were performed to assess the correlations between these muscle measurements and muscle mass, as well as the diagnostic value of low muscle mass (LMM) in elderly COPD patients.

The results showed that there were significant differences in  BMI, weight, SMI, gait speed, 5STS, grip strength, and CC between the LMM group and the normal muscle mass (NMM) group (P < 0.05). The ultrasound measurements showed that RAT, RF-CSA, and QFMT were significantly lower in the LMM group compared to the NMM group (P < 0.05). Similarly, the comparison of CT measurement parameters revealed that in the LMM group, both L1M CSA and PM CSA were significantly lower than those in the NMM group (P < 0.05). Correlation analysis revealed strong positive correlations between SMI and CC, L1M CSA, and RAT in the LMM group (p < 0.01), but no significant correlations were found with certain parameters. Receiver-operating characteristic curve analysis showed that the AUC values of PM CSA, QFMT, L1M CSA, RF-CSA and RAT in the diagnosis of LMM in elderly male COPD patients were 0.850, 0.830, 0.802, 0.722 and 0.684.

L1M CSA, RAT, RF-CSA, PM CSA, QFMT, and CC are positively correlated with muscle mass in elderly COPD patients with sarcopenia, and CC is a good screening index for predicting muscle mass. PM CSA and QFMT may be good indicators for the diagnosis of LMM in elderly male COPD patients with sarcopenia.