Sputum eosinophilia and short-term response to prednisolone in chronic obstructive pulmonary disease: a randomised controlled trial

Background Some patients wit chronic obstructive pulmonary disease (COPD) r espond toe corticosteroid therapy. Whether these patients have different ai rway pathology from other COPD patients is unclear. We tested the hypothesi s that response to prednisolone is related to the presence of eosinophilic airway inflammation. Methods We did a randomised, double-blind, crossover trial. Patients who ha d COPD treated with bronchodilators only were assigned placebo and 30 mg pr ednisolone daily for 2 weeks each, in a random order, separated by a 4-week washout period. Before and after each treatment period, we assessed patien ts with spirometry, symptom scores, the chronic respiratory disease questio nnaire (CRQ), incremental shuttle walk test, and induced sputum. Analysis w as done by intention to treat. Findings 83 patients were recruited, of whom 67 were randomised. The geomet ric mean sputum eosinophil count fell significantly after prednisolone (fro m 2.4% to 0.4%; mean difference six-fold [95% CI 3.1-11.4]) but not after p lacebo. Other sputum cell counts did not change. After stratification into tertiles by baseline eosinophil count, postbronchodilator forced expiratory volume in 1 s (FEV1) and total scores on the CRQ improved progressively af ter prednisolone from the lowest to the highest eosinophilic tertile, compa red with placebo. The mean change in postbronchodilator FEV1, total CRQ sco re, and shuttle walk distance with prednisolone compared with placebo in th e highest tertile was 0.19 L (0.06-0.32), 0.62 (0.31-0.93), and 20 m (5-35) , respectively. Interpretation Our findings suggest that eosinophilic airway inflammation c ontributes to airflow obstruction and symptoms in some patients with COPD a nd that the short-term effects of prednisolone are due to modification of t his feature of the inflammatory response. The possibility that sputum eosin ophilia identifies a subgroup of patients who particularly respond to long- term treatment with inhaled corticosteroids should be investigated.