Small-Airway Function Variables in Spirometry, Fractional Exhaled Nitric Oxide, and Circulating Eosinophils Predicted Airway Hyperresponsiveness in Patients with Mild Asthma

Patients with variable symptoms suggestive of asthma but with normal forced expiratory volume in 1 second (FEV ) often fail to be diagnosed without a bronchial provocation test, but the test is expensive, time-consuming, risky, and not readily available in all clinical settings. A cross-sectional study was performed in 692 patients with FEV ≥80% predicted; normal neutrophils and chest high-resolution computed tomography; and recurrent dyspnea, cough, wheeze, and chest tightness. Compared with subjects negative for AHR (n=522), subjects positive for AHR (n=170) showed increased FENO values, peripheral eosinophils (EOS), and R5-R20; decreased FEV , FEV /Forced vital capacity (FVC), and forced expiratory flow (FEFs) ( ≤.001 for all). Small-airway dysfunction was identified in 104 AHR patients (61.17%), and 132 AHR patients (25.29%) (