Reference values of the dorsal muscle group area for the diagnosis of sarcopenia using chest computed tomography in patients with chronic obstructive pulmonary disease: A prospective observational study

Background Sarcopenia is common in patients with chronic obstructive pulmonary disease (COPD) and is associated with poor prognosis. The dorsal muscle group area at the T12 vertebral level is useful in sarcopenia diagnosis; however, reference values for diagnosing sarcopenia are unavailable. This study aimed to establish the reference values for sarcopenia diagnosis using chest computed tomography scans in Japanese patients with COPD. Methods We analyzed data from the Ishinomaki COPD Network Registry and selected the participants in the Ishinomaki COPD Network Registry who visited our hospital between April 2024 and March 2025. Clinical parameters, including the dorsal muscle group area at the T12 vertebral level index (dorsal muscle group area at the T12 vertebral level/height ² ), were analyzed to identify factors associated with sarcopenia. Results This study included 353 patients. According to the sarcopenia status, the patients were divided into sarcopenia and non-sarcopenia groups. Propensity score matching and multivariate analyses were performed to compare baseline characteristics between the two groups. Multivariate regression logistic models revealed that the dorsal muscle group area at the T12 vertebral level index was an independent factor for predicting sarcopenia in patients with COPD. The area under the receiver operating characteristic curve for identifying sarcopenia in patients with COPD was 0.71, and the optimal cut-off value of the dorsal muscle group area at the T12 vertebral level index was 8.39. Conclusions Our study offers reference values for sarcopenia diagnosis using the dorsal muscle group area at the T12 vertebral level index evaluated using chest computed tomography in patients with COPD. Identifying patients with COPD in the early stages of sarcopenia can contribute to effective prevention and therapeutic measures.