An Evaluation of quantitative body composition on thoracic computed tomography and the effect on clinical severity in patients with chronic obstructive pulmonary disease

The aim of this study was to evaluate the effect on disease severity of the quantitative measurements of pectoral muscle area (PMA), pectoral muscle index (PMI), pectoral muscle density (PMD), subcutaneous adipose tissue (SAT) and mediastinal adipose tissue (MAT) taken on thoracic computed tomography (CT) of patients with chronic obstructive pulmonary disease (COPD), according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification. A retrospective screening was made of patients diagnosed with COPD and applied with thoracic CT and respiratory function tests. For patients with obstructive findings, a record was made of height, weight, body mass index, and smoking history (packet/year). On thoracic axial CT images, the PMA, PMI, PMD, SAT, and MAT values at the aortic arch level were calculated quantitatively using OsiriX software (Pixmeo, Switzerland). The patients were grouped as A-B-C-D according to the GOLD 2018 guidelines. Then two groups were formed as mild-moderate COPD (GOLD A-B) and severe COPD (GOLD C-D). The relationship was evaluated between clinical severity and quantitative body composition values according to the GOLD classification. A total of 80 patients diagnosed with COPD were included in the study comprising 61 males and 19 females. The GOLD A-B group included 43 (53.75%) patients and the GOLD C-D group, 37 (46.25%) patients. No significant difference was determined between the two groups in respect of the PMA, PMI, and PMD values (p=0.001). A statistically significant difference was determined between the groups in respect of the SAT and MAT values (p=0.001, p=0.002, respectively). A cutoff value of <30.04 in PMD (0.964; 95%CI:0.928-1) showed the best performance in predicting the mild-moderate COPD patients (GOLD A-B) with 92% sensitivity and 93% specificity. The results of this study demonstrated that PMD showed the best quantitative body composition performance in the differentiation of mild-moderate and severe COPD disease.