Bronchodilator reversibility - differences between asthma and COPD

Introduction: Currently the bronchodilator reversibility is not recommended to differentiate asthma from COPD, however physiopathological specificities of each disease contribute to different behaviour in response to the drug. Aims: To evaluate the differences in bronchodilator response between asthmatic and COPD patients and to determine which of bronchodilation criteria have the best ability to detect positive response in asthmatic and COPD patients. Methods: Cross-sectional study. The sample included 104 patients with asthma or COPD who performed lung function tests between January and March of 2018. The whole sample was analysed according to post-bronchodilator variation (∆) of lung function parameters and the post-bronchodilator reversibility was also characterized using a multiple bronchodilation criteria. Results: In this study, ∆FEV1 (forced expiratory volume in first second) and ∆Raw (airway resistance) was statistically higher in the group with asthma compared with the group with COPD. In the asthma group, the criteria ↓FRC (functional residual capacity)≥10%, ↓Raw≥35%, ↑FEF25%-75% (forced expiratory flow between 25% and 75% of vital capacity)≥20% and ↑FEV1 and/or ↑FVC (forced vital capacity)≥12% and 200 mL were those that presented a greater capacity of detecting a positive response to bronchodilator. On the other hand, the criteria ↑FEF25%-75%≥20% and ↓FRC≥10% were those that had the greater ability of detecting airway reversibility in COPD group. Conclusions: The analysis of post-bronchodilator FEV1 and Raw modifications, as well as the using of a combination of multiple bronchodilation criteria, contribute to a deeper characterization of bronchodilator reversibility in asthma and COPD.