What Does it Mean to Have An Asthma Component to My COPD?

Question: What Does it Mean to Have An Asthma Component to My COPD?

Answer: The traditional view that airway obstruction in asthma is completely reversible and in COPD is not, is no longer reasonable. Reversibility refers to resolution of airway obstruction with inhaled bronchodilators. It makes more sense to say that COPD defines having airflow limitation that is "partially reversible", the reversibility being greater after being treated with a bronchodilator. In contrast, asthma can be considered "less reversible", when it occurs chronically and is poorly controlled.

Although the definition of a significant bronchodilator response is somewhat controversial, the American Thoracic Society (ATS) defines it, in both asthma and COPD, as having an increase in FEV1 post-bronchodilator of at least 12% from baseline and of at least 200 milliliters.

When there is a reversible component to one's COPD, therefore an asthma component, there will be a significant increase in post-bronchodilator FEV1 (12% or greater). When there is very little to no reversibility, therefore no asthma component, there will be less than a significant increase post bronchodilator (less than 12%).

_Sources

_{Christopher B. Cooper, MD, Medscape Today. Assessment of Pulmonary Function in COPD: Response to Bronchodilator Therapy. Semin Respir Crit Care Med. 2005;26(2):246-252. © 2005 Thieme Medical Publishers.}

_{Hakima Ouksel, Nicole Meslier, Anne Badatcheff-Coat et.al. International Journal of Thoracic Medicine. Influence of Predicted FEV1 on Bronchodilator Response in Asthmatic Patients. Vol. 70, No. 1, 2003.}