PURPOSE: Several criteria of airway reversibility were used in chronic obstructive pulmonary disease (COPD) assessment. Nevertheless, their differences were not studied in further detail. The aim of this study was to investigate the differences and characteristics of airway reversibility accessed by different criteria in COPD patients.
METHODS: Post-bronchodilator FEV1 changed as percent predicted, value change and percent change from baseline were analyzed in 933 stable patients with mild-to-very-severe stages of COPD (66.8 +/- 8.4 years, mean FEV1 0.97L (40.86% predicted) by American Thoracic Society (ATS) and European Respiratory Society (ERS) criterion (Post-bronchodilator FEV1 change > 12% and > 200 ml from baseline) and percent predicted criterion (Post-bronchodilator FEV1 changed > 10% predicted). The volume response determined by FVC and flow response by FEV1 in vary severity of COPD were also studied.
RESULTS: Average improvements from baseline were 0.12L in FEV1 and 0.26L in FVC. FEV1 positive response rate accessed by ATS-ERS criteria was significant higher than that by percent prediction criteria (19.61% versus 13.50%, x2=39.14, p<0.001) after bronchodilator. The ratio of positive response rate of ATS-ERS criteria over percent predicted criteria in stage I, II, III and IV were 0.86: 1.22: 2.21: 3.02, respectively. Less increment of FEV1 but more increment of FVC was found as a function of the progress of COPD severity.
CONCLUSIONS: Assessments of airway reversibility varied between FEV1 changes as percent predicted and change from baseline. This difference will be larger with the progress of COPD severity. FVC should also be considered in determination of reversibility in COPD.
CLINICAL IMPLICATIONS: This finding confirmed our hypothesis that there were differences between different criteria in the assessment of airway reversibility in COPD, and this difference was related to the severity. This difference should be considered when the airway reversibility is assessed.
DISCLOSURE: The following authors have nothing to disclose: Wenhua Jian, Jinping Zheng, Yi Hu, Yin Li, Tian'en Jin, Pingping Guo, Mengjie Jiang, Bo Yun, Yi Gao, Jiaying An
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