Clinical symptoms and radiologic features of airway abnormalities assessed by impulse oscillometry in patients with chronic obstructive pulmonary disease

Background: Airway abnormalities assessed by impulse oscillometry (IOS) were common in patients with chronic obstructive pulmonary disease (COPD). However, most studies only used difference from R5 to R20 (R5-R20) > 0.7kPa/L/s to diagnose airway abnormalities, which may ignore the value of other IOS indicators in the diagnosis of airway abnormalities. Our study aimed to comprehensively assess clinical symptoms and radiologic features of airway abnormalities in COPD patients in China. Methods: : We enrolled 805 COPD patients from a part of ECOPD cohort, they underwent questionnaires, symptom scores, lung function, IOS and HRCT. The criteria of airway abnormalities were based on standardized IOS reference values. Logistic regression was used to analyze risk factors of airway abnormalities. The associations between acute exacerbation of COPD (AECOPD) in the previous year and airway abnormalities were assessed by Poisson regression. Logistic regression was used to assess the associations between CT imaging and airway abnormalities. Results: : The proportion of airway abnormalities evaluated by other indicators increased gradually with COPD severity except for R20. Multivariate logistic analysis showed dyspnea, low FEV1% predicted and airway obstruction were associated with risk of airway abnormalities. Compared with normal airway group, airway abnormalities group had more clinical symptoms (wheeze and dyspnea) and higher mMRC and CAT scores. Airway abnormalities assessed by X5 and AX had more emphysema, gas trapping and higher risk of AECOPD in the previous year. Conclusions: : Reactance (X5, AX) assessment of airway abnormalities had more clinical symptoms, emphysema, gas trapping and higher risk of AECOPD in the previous year.