Abstract
Background: The differential diagnosis in persistent airway limitation is sometimes not so clear in older adults. Airway eosinophilia and airway hyperresponsiveness may develop in some cases with chronic obstructive lung disease (COPD), independent of asthma. However, little is known about clinical significance of these phenotypes of COPD in detail. Aims and objectives: This clinical study was designed to examine prevalence of airway eosinophilia and airway hyperresponsiveness in COPD who have no symptom and no past history of asthma, and to examine involvement of these pathophysiological features of asthma in the management and therapy for COPD. Methods: Sputum examination via qualitative and quantitative procedures was performed in stable COPD (GOLD 1–3). When sputum eosinophils were qualitatively (≥+) or quantitatively assessed (≥3%), ciclesonide (inhaled glucocorticosteroids) was added on bronchodilators. In cases with FEV1 ≥ 70% of predicted values, acetylcholine provocation test was examined for assessment of airway hyperresponsiveness. Therapeutic effect was evaluated using spirometry and COPD assessment test (CAT). Results: Sputum eosinophils were observed in 65 (50.4%) of 129 subjects using qualitative analysis; in contrast, lower grade (>0%) and higher grade (≥3%) were observed in 15 (20.3%) and 25 (33.8%) of 74 subjects using quantitative analysis. Airway hyperresponsiveness developed in 46.9% of these subjects with sputum eosinophils. Exacerbations occurred much more frequently in lower-grade airway eosinophilia without ciclesonide than in higher-grade airway eosinophilia with ciclesonide. Airway hyperresponsiveness significantly increased frequency of exacerbations in COPD with both lower and higher grade in airway eosinophilia. Addition of ciclesonide to indacaterol markedly improved lung function (FEV1, IC), CAT score, and reliever use in these subjects with airway eosinophilia determined by qualitative analysis. However, ciclesonide was less effective in improving these values in subjects with airway hyperresponsiveness than in those without airway hyperresponsiveness. Conclusions: Airway eosinophilia and airway hyperresponsiveness are complicated with 25–50% of COPD that have no symptom and history for asthma. These phenotypes of COPD are closely related to symptom stability and reactivity to glucocorticosteroids. These phenotypes may play key roles for advancement of the management and therapy of this disease.
Highlights
Chronic obstructive lung disease (COPD) is characterized by persistent respiratory symptoms and persistent airflow limitation due to airway and/or alveolar abnormalities (The Global Strategy for the Diagnosis, Management and Prevention of COPD, Global Initiative for Chronic Obstructive Lung Disease (GOLD), 2017)
The cutoff values of percentage of eosinophil have not been standardized yet for airway eosinophil inflammation using the quantitative methods in sputum examination, it is generally considered that ≥3% of eosinophil may be meaningful for airway eosinophil inflammation, because sputum eosinophilia is less than 1% in healthy adults (Belda et al, 2000)
To determine whether airway eosinophil inflammation has an influence on COPD, the relationship between GOLD stage and sputum eosinophilia was examined
Summary
Chronic obstructive lung disease (COPD) is characterized by persistent respiratory symptoms (dyspnea, chronic cough, or sputum production) and persistent airflow limitation due to airway and/or alveolar abnormalities (The Global Strategy for the Diagnosis, Management and Prevention of COPD, Global Initiative for Chronic Obstructive Lung Disease (GOLD), 2017). COPD has an old onset with slowly progressive symptoms associated with a poor response to inhaled therapy and with longer-term smoking; in contrast, asthma generally has an early onset with intermittent symptoms associated with a good response to inhaled therapy (The Global Strategy for the Diagnosis, Management and Prevention of COPD, Global Initiative for Chronic Obstructive Lung Disease (GOLD), 2017). It may be clinically difficult to separate accurately asthma from COPD when patients present reduced lung function because diagnostic criteria for asthma due to objective findings have not been established yet. Little is known about clinical significance of these phenotypes of COPD in detail
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