Characteristics of study subjects
| Mean (SD) | Median (interquartile range) | |
|---|---|---|
| FEV1=forced expiratory volume in 1 second; FEF25—75=mid forced expiratory flow; Kco=carbon monoxide transfer coefficient. Data are listed as mean (SD) for normally distributed variables and as median (interquartile range) for non-parametric variables. The airway cell counts and exhaled nitric oxide measurement are the values at optimum asthma control following the steroid trial. | ||
| Age (years) | 54.3 (11.7) | |
| Duration of asthma (years) | 30.8 (16.3) | |
| Dose of inhaled steroid (μg beclomethasone) | 1000 (800–2000) | |
| Baseline FEV1 (% predicted) | 60.6 (21.8) | |
| Best FEV1 (% predicted) | 72.8 (21.7) | |
| Baseline FEF25–75 (% predicted) | 38.7 (23.2) | |
| Best FEF25–75 (% predicted) | 50.8 (27.7) | |
| Kco (% predicted) | 101.0 (21.8) | |
| Log PC20 to histamine | –0.18 (0.7) | |
| Post-steroid absolute neutrophil count (×106 cells/ml sputum plug) | 22.9 (12.0–33.6) | |
| Post-steroid percentage neutrophil count | 73.0 (48.0–81.0) | |
| Post-steroid absolute macrophage count (×106 cells/ml sputum plug) | 8.0 (6.8–14.0) | |
| Post-steroid percentage macrophage count | 25.0 (18.0–52.0) | |
| Post-steroid exhaled nitric oxide (ppb) | 6.1 (4.2–9.5) | |
| Wall area as % bronchial cross sectional area (WA%) | 75.5 (3.2) | |
| Wall thickness/bronchial diameter ratio (T/D ratio) | 0.26 (0.02) | |