Clinical and Airway Inflammation Features of COPD Patients with Positive Bronchodilator Test

Abstract

Objective: To explore the difference in clinical characteristics and airway inflammation in chronic obstructive pulmonary disease (COPD) patients on the positive bronchodilator tests.

Study design: Descriptive study.

Place and duration of study: Affiliated Hospital of Shaoxing University, Shaoxing, China, from January to December 2017.

Methodology: A total of 200 COPD patients were subjected to COPD Assessment Test (CAT), modified Medicine Research Council (mMRC) score, 6-minute walk distance, Rating of Perceived Exertion Scale (Borg), pulmonary function, serum IgE, and cell count in induced sputum. They were divided into a positive group and a negative group according to the response to the bronchodilator test, and the results were compared.

Results: There were 46 cases (23.00%) in the positive group, and 154 cases (77.00%) in the negative group. There were evident differences in the history of smoking and serum IgE. The positive group had better outcomes than those of the negative group regarding forced expired volume in one second to total predicted value ratio (FEV1% pred), forced vital capacity to total predicted value ratio (FVC% pred), improvement rate of maximum expiratory flow of 75% of lung capacity (MEF75%), and MEF50%. CAT score, mMRC score, Borg score, meters in 6-minute walking test (all p<0.05). There was no significant difference in cell count in induced sputum between the two groups.

Conclusion: COPD patients having a positive response to the bronchodilator had better lung function, better CAT score, better mMRC score, and Borg scale score. They also had further 6-minute walking distance. It suggests that a positive bronchodilator response might be a clinical phenotype of COPD.