Chronic mucus hypersecretion in severe asthma

Introduction: Chronic mucus hypersecretion (CMH) is common in asthmatics but its clinical significance in severe asthma and relationship to inflammatory phenotypes is not well understood. Objectives: We aimed to describe the prevalence and associated features of CMH in severe asthma. Methods: Patients (≥18 years) with a diagnosis of asthma (DJ45-DJ45.9) who fulfilled the ERS/ATS 2014 guidelines for severe asthma were included in the SATS study (n=120). Lung function and disease control were assessed. CMH was defined as excess daily sputum production for at least 3 months in two consecutive years. Sputum was obtained from 80% of patients. Sputum neutrophilia was defined as ≥61% neutrophils and eosinophilia as ≥3% eosinophils. Results: CMH was reported by 54 patients (45%). They had significantly poorer asthma control (mean ACQ score 2.39 (95% CI 2.07-2.71) versus 1.49 (95% CI 1.25-1.73)(p Conclusion: Chronic mucus hypersecretion in severe asthma is associated with significantly poorer asthma control. The pathogenic mechanism of CMH needs further exploration, but does not appear to be associated with a specific underlying inflammatory phenotype.