Typing of chronic obstructive pulmonary disease using high-resolution computed tomography and the association with smoking, airway inflammation, and common comorbidities

Authors: ZHENG LIU, YAN WANG, YING LIU, MENGMIAO PEI, JING LI, FANG SHI, PEIXIU LI

Abstract: Background/aim: This study performed typing of chronic obstructive pulmonary disease (COPD) using high-resolution computed tomography (HRCT) to determine the association with smoking, matrix metalloproteinases, and common comorbidities. Materials and methods: The study enrolled 94 hospitalized patients. Participants were divided into a group of 69 current and former smokers (group A) and a group of 25 that had never smoked (group B). Patients were also divided into 3 categories according to the degree of emphysema and bronchial wall thickness using HRCT to determine the association with levels of matrix metalloproteinase 9 (MMP-9) and TIMP-1, as well as associated comorbidities. These three categories were: type A - no or mild emphysema, with or without bronchial wall thickening; type E - emphysema without bronchial wall thickening; and type M - both emphysema and bronchial wall thickening. Results: The low attenuation area (LAA) scores in group A patients were higher than those in group B (t = 2.86, P < 0.01); correlation analysis showed that smoking was associated with a decline of the forced expiratory volume in 1 s and forced vital capacity ratio (FEV1/ FVC%) and higher LAA scores in patients with COPD (F = 4.46, F = 8.20, P < 0.05). The levels of MMP-9 in group A were higher than those in group B (t = 3.65, P < 0.01). Among COPD patients with more than 3 comorbidities, there were statistically significant differences in both the smoking group and the nonsmoking group (chi-square = 12.08, P < 0.01). When compared to type A patients, who had coincident cardiovascular diseases in the smoking group, patients of type M and E showed statistically significant differences (F = 2.42 and 2.12, P < 0.05). Conclusion: Emphysema was more severe in smokers. Metalloproteinase levels in smokers were higher than those in nonsmokers. Moreover, comorbidities were more severe in smokers.

Keywords: Smoking, COPD, high-resolution computed tomography, emphysema, chronic bronchitis, metalloproteinase, comorbidities

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