Fig. 3

A Pearson correlation analysis shown in cor-heatmap plot to explore the correlation between muscle areas, *P-value < 0.05, #P-value > 0.05. B The ROC curve shows the accuracy of using the chest muscle area to distinguish between patients with COPD and patients who did not have COPD. C Cluster analysis heatmap shows three chest muscles (pectoralis major muscle, intercostal muscle, and musculus serratus anterior muscle) expression levels in the COPD and non-COPD groups. Abbreviations: AUC, area under the ROC curve