Clinical associations of mucus plugging in moderate to severe asthma

Background: Mucus plugging is recognized as a contributory factor to airway obstruction and symptoms in persistent asthma. Objective: We aimed to determine phenotypic associations of mucus plugging in patients with moderate to severe asthma in a real-life clinic setting.Methods: Mucus plugs (MPs) were identified by a thoracic radiologist upon high-resolution computed tomography imaging. A MP score was subsequently calculated and analyzed along with type 2 biomarkers, spirometry, severe exacerbations, and asthma control for 126 patients with moderate to severe asthma before biologic therapy.Results: Asthma patients with MP had significantly worse FEV 1%, forced expiratory flow at 25% to 75% of FVC percent, and FEV 1/FVC as well as higher levels of peripheral blood eosinophils, FeNO, total IgE, and Aspergillus fumigatus IgE titers, and had previously experienced more frequent severe exacerbations. FEV 1/FVC, more than two exacerbations per year, blood eosinophils, total IgE, and A fumigatus IgE titers were associated with MPs after adjusting for confounders.Conclusions: Poorly controlled asthma patients with MPs exhibited significantly worse airflow obstruction and greater type 2 inflammation associated with more frequent severe exacerbations. Impaired spirometry, more frequent exacerbations, raised blood eosinophils, total IgE, and A fumigatus IgE increased the likelihood of MPs.