IOS, impulse oscillometry; FENO, fractional exhaled nitric oxide; CV, Coefficient of variance; BMI, body mass index; FVC, forced vital capacity; FEV1, forced expiratory volume in 1 second; FEV3, FEV in 3 seconds; PEF, peak expiratory flow; FEF25%, forced expiratory flow at 25% of FVC; FEF50%, FEF at 50% of FVC; FEF75%, FEF at 75% of FVC; FEF25%-75%, FEF at 25% to 75% of FVC; EOS, eosinophils; ppb, parts per billion; PD20, provocative dose causing a 20% fall in FEV in the first second; R5, total airway resistance at 5 Hz; R20, central airway resistance at 20 Hz; R5-R20, peripheral airway resistance as the difference between 5 and 20 Hz; X5, reactance at 5 Hz; Fres, resonant frequency.
Small-airway dysfunction was identified if 2 of the variables FEF50%, FEF75% and FEF25%-75% were lower than 80%.
Mean (SD) values.
Median (IQR) values
§ n = 333, 92 for positive bronchial provocation, 241 for negative bronchial provocation
n = 619, 153 for positive bronchial provocation, 466 for negative bronchial provocation
Bold font indicates statistical significance.
Table 2. Spearman correlation between PD20 and other variables in BHR-positive subjects.