Small Airway Dysfunction in Cough Variant Asthma: Prevalence, Clinical, and Pathophysiological Features

• Published in: Frontiers in physiology 2022-01, Vol.12, p.761622-761622
• Main Authors: Yi, Fang, Jiang, Ziyu, Li, Hu, Guo, Chunxing, Lu, Hankun, Luo, Wei, Chen, Qiaoli, Lai, Kefang
• Format: Article
• Language: English
• Subjects: airway inflammation; cough severity; cough variant asthma; Physiology; prevalence; small airway dysfunction
• ISSN: 1664-042X; 1664-042X
• DOI: 10.3389/fphys.2021.761622

Small airway dysfunction (SAD) commonly presents in patients with classic asthma, which is associated with airway inflammation, disease severity, and asthma control. However, the prevalence of SAD, its relationship with cough severity and airway inflammation, and its development after antiasthmatic treatment in patients with cough variant asthma (CVA) need to be clarified. This study aimed to investigate the prevalence of SAD and its relationship with clinical and pathophysiological characteristics in patients with CVA and the change in small airway function after antiasthmatic treatment. We retrospectively analyzed 120 corticosteroid-naïve patients with CVA who had finished a standard questionnaire and relevant tests in a specialist cough clinic, such as cough visual analog scale (VAS), differential cells in induced sputum, fractional exhaled nitric oxide (FeNO) measurement, spirometry, and airway hyper-responsiveness. Information of 1-year follow-up was recorded in a part of patients who received complete cough relief after 2 months of treatment. SAD was defined as any two parameters of maximal mid-expiratory flow (MMEF)% pred, forced expiratory flow at 50% of forced vital capacity (FEF50%) pred, and forced expiratory flow at 75% of forced vital capacity (FEF75%) pred measuring