Diagnostic value of CT in patients with stable chronic obstructive pulmonary disease at high altitude: Observational study

Abstract

This research aims to explore the diagnostic value of computed tomography (CT) indicators in patients with stable chronic obstructive pulmonary disease (COPD) in a plateau of China, and to find out the correlation between CT indexes and lung function and symptoms. This study screened out 53 stable COPD patients and 53 healthy people through inclusion and exclusion criteria in Hongyuan county, Aba Prefecture, Sichuan Province, between July 2020 and December 2020, and then collected their baseline data, conducted lung function tests and chest CT scans, and collected COPD Assessment Test (CAT), modified Medical Research Council Dyspnea Scale (mMRC) scores. The CT indexes of the 2 groups were compared, binary logistic regression was used to analyze the influence of COPD, the receiver operating characteristic (ROC) curve was used to evaluate the diagnostic value of the CT indexes for COPD. The Spearman test was used to understand the correlation analysis between the CT indexes and lung function, symptom score, and the number of acute exacerbations. Multiple linear regression was used to analyze the influencing factors of lung function. The percentage of low-attenuation areas less than -950 Hounsfield units (%LAA-950; t = -4.387,P = 0), percentage of wall area (WA%; t = -4.501, P = 0), and thickness-diameter ratio (TDR; t = -4.779, P = 0) in the COPD group were higher than those in the normal group. ROC shows that: %LAA-950 (P = .047) and TDR (P = .034) were independent influence in COPD in the plateau. %LAA-950 combined with TDR (AUC = 0.757, P < .001) had the value of diagnosis of COPD in the plateau. All 3 indexes are negatively correlated with lung function, and positively correlated with the symptoms and the number of acute exacerbations. Multiple linear regression analysis showed that the main factors for decrease of ratio of measurement to prediction of forced expiratory volume to the first second (FEV1%) included %LAA-950 (OR = -0.449, P < .001) and WA% (OR = -0.516, P < .001). CT indexes have a certain diagnostic value in patients with stable COPD at high altitude.