Can inhaled corticosteroid reduce exacerbation in asthma COPD overlap?
Published online: January 15, 2020
Asthma– chronic obstructive pulmonary disease (COPD) overlap (ACO) is a condition that is characterized by overlapping clinical features from both diseases. Due to lack of evidence, there has been a debate regarding whether inhaled corticosteroid (ICS) is effective in patients with ACO. This is because patients with characteristics of both asthma and COPD have been usually excluded from clinical trials. Moreover, there is still no uniform definition of ACO.
Patients with COPD enrolled in the Korean COPD subgroup study cohort were intensively assessed for asthma overlap and prospectively followed-up for 1 year. In a recent article published in The Journal of Allergy & Clinical Immunology: In Practice, Yong Suk Jo et. al used 5 sets of well-known diagnostic criteria for ACO and examined the association between ICS use and exacerbations, according to the different diagnostic criteria.
The prevalence of ACO varied from 3.0% to 24.7% according to each definition. Among 5 ACO definitions, ICS showed an effect on exacerbations in only 2. In specialists’ diagnosis of ACO and Global Initiative for Asthma (GINA)-defined ACO, ICS significantly reduced exacerbations, while it did not in non-ACO (COPD only).
To identify factors that may predict a positive response to ICS, several components of ACO criteria were evaluated. The only factor associated with reduction of exacerbation by ICS was a blood eosinophil count ≥ 300 cells/µL (incidence rate ratio = 0.52, P = 0.03). Interestingly, there was no difference in exacerbation rate between patients with and without ICS among COPD patients with a history of asthma. Similarly, use of ICS was not associated with reduced exacerbations among COPD patients with positive bronchodilator response, history of allergic disease, or IgE>100 IU.
These findings suggest clinicians should be cautious in prescribing ICS to ACO patients. History of asthma or positive bronchodilator response may not be indicative of ICS response in patients with COPD. A high blood eosinophil count serves as a good indication for ICS treatment, irrespective of whether or not the patient fulfills any of the diagnostic criteria of ACO.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.