Different Smoking Statuses on Survival and Emphysema in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Objective: To investigate the association between different smoking statuses and survival and emphysema in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Methods: This retrospective study included patients admitted from October 2014 to September 2017. Demographic, clinical, laboratory, imaging, impulse oscillometry, and traditional pulmonary function data were collected. The relationship between smoking and EI was analyzed via binary logistic regression after adjusting for other factors. Survival was analyzed using the Kaplan-Meier method and the log rank test. Results: The patients with AECOPD (357 cases) were identified (and stratified into three groups: never smoked (NS; n=83), former smokers (FS, n=118), and current smokers (CS; n=156). Compared with CS, NS were older and predominantly female. No differences were observed in respiratory symptoms and acute exacerbation between CS and NS. NS had higher resistance and reaction in the central and peripheral airways, while CS exhibited more severe diffuse dysfunction. CS demonstrated more severe and extensive emphysema. Smoking was an independent risk factor for emphysema after adjusting for age, forced expiratory volume in the first second over predicted value, BMI, leukocyte count, and carbon monoxide transfer coefficient. No difference in 5-year survival rates between NS and CS was established. Conclusion: CS has the worst pulmonary function, suggesting a more important destruction of the lung parenchyma, while AECOPD without smoking risk factors mostly affects the airways. Impulse oscillometry can be used for imaging airway-dominant AECOPD. There was no difference in the 5-year survival rate.