Eosinophilic airway inflammation as a complication of COPD, and the usefulness of ICS on these cases

Abstract

Backgrounds: The differential diagnosis in patients with persistent airway limitation is sometimes not so clear in older adults. Eosinophil inflammation in the airways is observed in some cases with COPD, independent of asthma. However, little is known about airway eosinophilia in COPD. Aims: This retrospective clinical study was designed how airway eosinophilia develop in patients with COPD who have no past history of asthma, and whether addition to inhaled glucocorticosteroid (ICS) on these cases is beneficial. Methods: Sputum examination was carried out in the stable COPD (GOLD 2-3) with daily inhaled long-acting bronchodilators (LABAs and LAMAs). When airway eosinophilia was diagnosed by qualitative (+) or quantitative assessment (>2%), ICS was added on these patients. COPD assessment test (CAT) and lung function test were followed up. In cases with FEV 1 > 1.7 L, acethylcholine provocation test was examined for assessment of airway hyperresponsiveness (AHR). Results: Eosinophils in sputum were observed in 35 (45.5%) of 77 cases who have no clinical features of asthma. In 10 cases (47.6%) of 21 cases, the value of PC 20 in the provocative test was less than 8000 μg/mL. After administration of ICS, CAT score were decreased from 8.9 to 5.4 points, and FEV 1 and IC were further increased by 147.0 and 227.6 mL, respectively (each P 1 /FVC is still less than 70% in these all cases. Conclusions: Airway eosinophilia and AHR, which are characteristic features of asthma, develop in approximate 45% of COPD independent of asthma. Addition of ICS to bronchodilators is very effective on COPD with airway eosinophilia.