Demographic characteristics of study subjects
| Variables | SRA (n=33) | Moderate asthma (n=29) | Naïve asthma (n=21) | Normal subjects (n=20) | p Value |
| Age (years) | 54±13 | 51±17 | 55±9 | 52±10 | 0.825 |
| Gender (F/M) | 21/12 | 16/10 | 12/9 | 11/9 | 0.650 |
| Atopy | 19/33 | 17/29 | 12/21 | 0 | 0.726 |
| Duration of disease (years) | 37 (31–44) | 31 (27–38) | 32 (26–37) | ND | 0.345 |
| BMI (kg/m2) | 28±5 | 27±4 | 27±4 | 26±4 | 0.720 |
| FeNO (ppb) | 21 (18–61) | 19 (16–44) | 34 (17–74) | 12 (10–13) | 0.003† |
| BHR (PD15, mg) | 0.08±0.03 | 0.15±0.06 | 0.2±0.09 | >2 | 0.005* |
| FEV1 (% predicted) | 66 (55–73) | 81 (76–108) | 86 (73–97) | 94 (85–98) | 0.001* |
| PB FEV1 (% predicted) | 72 (59–84) | 93 (84–114) | 90 (81–98) | 95 (88–99) | 0.003* |
| FVC (% predicted) | 87±17 | 101±16 | 95±11 | 96±10 | 0.005* |
| FEV1/FVC (%) | 63±7 | 71±7 | 72±8 | 87±6 | 0.001* |
| Tlco (% predicted) | 77±12 | 88±10 | 92±7 | 95±6 | 0.003* |
| FRC (% predicted) | 110±23 | 97±15 | 90±12 | 89±12 | 0.001* |
| Treatment regimens | |||||
| ICS (number-dose‡) | 33–1440 | 29–640 | 0 | 0 | |
| LABA | 33 | 29 | 0 | 0 | |
| Oral CS | 21 | 0 | 0 | 0 | |
| Omalizumab/LTRA | 5/12 | 0/8 | 0 | 0 |
Normally distributed data are presented as mean±SD and skewed data are presented as median (IQR).
↵* Significant p values pertaining to differences among the four groups all in favour of SRA.
↵† Significant p values pertaining to differences among the four groups in favour of those with steroid-naïve asthma.
↵‡ Dose expressed as equivalent to budesonide in μg.
BMI, body mass index; BHR, bronchial hyper-responsiveness; CS, corticosteroids; FeNO, fraction of exhaled nitric oxide; FEV1, forced expiratory volume in 1 s; FRC, functional residual capacity; FVC, forced vital capacity; ICS, inhaled corticosteroids; LABA, long-acting β2 agonists; LTRA, leukotriene receptor antagonists; PB FEV1, postbrochodilation forced expiratory volume in 1 s; SRA, severe refractory asthma; Tlco, carbon monoxide transforming factor.