Different thresholds of bronchodilator response in steroid-naïve asthma patients with pre-bronchodilator forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) <0.7 versus FEV1/FVC ≥0.7 measured from spirometry with the highest reversibility chosen from each patient (N=219)
| pre-BD FEV1/FVC ≥0.7 (n=151) | pre-BD FEV1/FVC <0.7 (n=68) | p-value | |
| Absolute change ≥200 mL | 80 (53.0%) | 48 (70.6%) | 0.018 |
| Absolute change ≥400 mL | 32 (21.2%) | 20 (29.4%) | 0.229 |
| ΔFEV1 % of the initial FEV1 ≥12% and 200 mL | 40 (26.5%) | 38 (55.9%) | <0.001 |
| ΔFEV1 % of the initial FEV1 ≥15% and 400 mL | 21 (13.9%) | 18 (26.5%) | 0.035 |
| ΔFEV1 % of the initial FEV1 ≥12% and 400 mL | 26 (17.2%) | 19 (27.9%) | 0.074 |
| ΔFEV1 % of the initial FEV1 ≥15% and 200 mL | 27 (17.9%) | 30 (44.1%) | <0.001 |
| ΔFEV1 % of the predicted FEV1 ≥8% | 58 (38.4%) | 38 (55.9%) | 0.019 |
| ΔFEV1 % of the predicted FEV1 ≥9% | 46 (30.5%) | 33 (48.5%) | 0.015 |
| ΔFEV1 % of the predicted FEV1 ≥10% | 37 (24.5%) | 29 (42.6%) | 0.010 |
| None of the thresholds was fulfilled | 70 (46.4%) | 19 (27.9%) | 0.012 |
Data are presented as n (%).