Investigating sarcopenia and mucus plugging by chest computed tomography in patients with severe chronic obstructive pulmonary disease.

To determine the relationship between mucus plugging and CT-derived parameters of sarcopenia in routine chest CT-scans. Patients with advanced Chronic Obstructive Lung Disease (COPD GOLD 3 or 4) were investigated. Mucus plug score (MPS) and cross-sectional muscle area (CSA) of pectoralis and erector spinae muscle of each patient was assessed by two radiologists. Statistics included non-parametric group comparison, multivariate analysis, and inter- and intrarater agreement. Median age of 123 patients (47 female) was 66 years. In 63 patients (15 females) no mucus plugging was found. 31 patients (15 females) had 1-2 mucus plugs and 29 patients (17 females) had a mucus plug of ≥ 3. PMCSA and ESMCSA were not independently associated with MPS; however, the association between PMCSA and MPS was modified by body weight, with a significant negative correlation between body weight and PMCSA in patients with higher MPS (≥ 3). Inter- and intrarater agreement was very good (ICC 0.899 or higher). Imaging based evaluation of MPS and CSA is reliable on routine chest CT-scans. Patients with more advanced COPD exhibited a higher MPS and larger PMCSA relative to body weight, possibly due to the greater muscular effort required for breathing.