1. Small Airway Dysfunction in Asthma Is Associated with Perceived Respiratory Symptoms, Non-Type 2 Airway Inflammation, and Poor Responses to Therapy
- Author
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Lei Wang, Xin Zhang, Ying Liu, Zhihong Chen, Hong Lin Li, Li Zhang, Min Xie, Ji Wang, Hong Ping Zhang, Brian G. Oliver, Bin Miao Liang, and Gang Wang
- Subjects
Adult ,Male ,Pulmonary and Respiratory Medicine ,Spirometry ,medicine.medical_specialty ,Visual Analog Scale ,Visual analogue scale ,Severity of Illness Index ,Bronchial Provocation Tests ,Interferon-gamma ,Internal medicine ,medicine ,Humans ,Prospective Studies ,Treatment Failure ,Respiratory system ,Asthma ,medicine.diagnostic_test ,business.industry ,Interleukin-8 ,Sputum ,medicine.disease ,respiratory tract diseases ,Cross-Sectional Studies ,Dyspnea ,Asthma Control Questionnaire ,Female ,Bronchoconstriction ,Bronchial Hyperreactivity ,medicine.symptom ,Airway ,business ,Follow-Up Studies - Abstract
Background: Emerging evidence has indicated that small airway dysfunction (SAD) contributes to the clinical expression of asthma. Objectives: The aim of the study was to explore the relationships of SAD assessed by forced expiratory flow between 25 and 75% (FEF25–75%), with clinical and inflammatory profile and treatment responsiveness in asthma. Method: In study I, dyspnea intensity (Borg scale), chest tightness, wheezing and cough (visual analog scales, VASs), and pre- and post-methacholine challenge testing (MCT) were analyzed in asthma patients with SAD and non-SAD. In study II, asthma subjects with SAD and non-SAD underwent sputum induction, and inflammatory mediators in sputum were detected. Asthma patients with SAD and non-SAD receiving fixed treatments were prospectively followed up for 4 weeks in study III. Spirometry, Asthma Control Questionnaire (ACQ), and Asthma Control Test (ACT) were carried out to define treatment responsiveness. Results: SAD subjects had more elevated ΔVAS for dyspnea (p = 0.027) and chest tightness (p = 0.032) after MCT. Asthma patients with SAD had significantly elevated interferon (IFN)-γ in sputum (p < 0.05), and Spearman partial correlation found FEF25–75% significantly related to IFN-γ and interleukin-8 (both having p < 0.05). Furthermore, multivariable regression analysis indicated SAD was significantly associated with worse treatment responses (decrease in ACQ ≥0.5 and increase in ACT ≥3) (p = 0.022 and p = 0.032). Conclusions: This study indicates that SAD in asthma predisposes patients to greater dyspnea intensity and chest tightness during bronchoconstriction. SAD patients with asthma are characterized by non-type 2 inflammation that may account for poor responsiveness to therapy.
- Published
- 2021
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