Association of blood eosinophils and plasma periostin with FEV(1) response after 3-month inhaled corticosteroid and long-acting beta(2)-agonist treatment in stable COPD patients

BACKGROUND: COPD patients with increased airway eosinophilic inflammation show a favorable response to inhaled corticosteroids (ICS) in combination with a long-acting bronchodilator. Recent studies have demonstrated a significant correlation of sputum eosinophilia with blood eosinophils and periostin. We investigated whether high blood eosinophils and plasma periostin were associated with an improvement in forced expiratory volume in 1 second (FEV(1)) after 3-month treatment with ICS/long-acting beta(2)-agonist (LABA) in stable COPD patients. PATIENTS AND METHODS: Blood eosinophils and plasma periostin levels were measured in 130 stable COPD subjects selected from the Korean Obstructive Lung Disease cohort. Subjects began a 3-month ICS/LABA treatment after washout period. RESULTS: High blood eosinophils (>260/µL, adjusted odds ratio =3.52, P=0.009) and high plasma periostin (>23 ng/mL, adjusted odds ratio =3.52, P=0.013) were significantly associated with FEV(1) responders (>12% and 200 mL increase in FEV(1) from baseline after treatment). Moreover, the addition of high blood eosinophils to age, baseline positive bronchodilator response, and FEV(1) <50% of the predicted value significantly increased the area under the curve for prediction of FEV(1) responders (from 0.700 to 0.771; P=0.045). CONCLUSION: High blood eosinophils and high plasma periostin were associated with improved lung function after 3-month ICS/LABA treatment. In particular, high blood eosinophils, in combination with age and baseline lung function parameters, might be a possible biomarker for identification of COPD patients with favorable FEV(1) improvement in response to ICS/LABA treatment.