Using the 6-min walk test to assess the clinical response to mepolizumab and conventional therapy in severe eosinophilic asthma

Background Severe asthma limits exercise to avoid respiratory symptoms. The objective of the present study was to investigate the role of the 6-min walk test (6MWT) in severe asthma. Methods Consecutive patients with severe eosinophilic asthma were enrolled. A 6MWT was performed before and after 12 months. Inhaled therapy dose, oral corticosteroids dose, pulmonary function tests, eosinophil blood count, fractional exhaled nitric oxide (FeNO), Asthma Control Test (ACT) score and responses to the Asthma Quality of Life Questionnaire (AQLQ) were also recorded. Results Of the 22 patients enrolled, 13 were treated with mepolizumab 100 mg every 4 weeks in addition to conventional therapy and nine with conventional therapy only. The majority of the patients were treated with high-dose inhaled corticosteroids/long-acting β-agonists/long-acting muscarinic receptor antagonists, while approximately half were on continuous oral corticosteroids. After 12 months, the mepolizumab group only showed a significant improvement in pulmonary function tests (percentage forced expiratory volume in 1 s and percentage forced expiratory flow at 25–75% forced vital capacity (FEF25–75%), both p0.05). By paired comparisons, statistically significant improvements of the mean 6-min walk distance (6MWD) were observed in the mepolizumab (p