Comparison of characteristics of patients with severe asthma with and without frequent exacerbations
| Exacerbations | p-value | ||
| ≥3 | 1 | ||
| Subjects n | 39 | 24 | |
| Female % | 79.5 | 62.5 | 0.14 |
| Age yrs | 38.3±13.8 | 46.7±13.1 | 0.02 |
| Asthma duration yrs | 12.0 (2–53) | 24.5 (4–57) | 0.01 |
| Dose ICS# µg·day−1 | 1600 (1600–4800) | 1600 (1600–4800) | 0.38 |
| Smoking history pack-yrs | 0 (0–10) | 0 (0–9) | 0.65 |
| Positive family history asthma % | 59.0 | 29.2 | 0.02 |
| Atopic % | 69.2 | 45.8 | 0.07 |
| Baseline FEV1 % pred | 72.9±23.6 | 71.3±26.2 | 0.82 |
| Reversibility FEV1 % change | 11.6 (0–44) | 7.5 (−1–26) | 0.01 |
| PC20 histamine mg·mL−1 | 0.29 (0.02–8.0) | 2.73 (0.02–8.0) | 0.07 |
| Exacerbations last year | 4 (3–7) | 1 (1–1) | <0.001 |
| Hospitalisations last year | 0 (0–8) | 0 (0–1) | 0.004 |
| Emergency visits last year | 2 (0–10) | 0 (0–5) | 0.05 |
Data are presented as mean±sd or median (range), unless otherwise stated. ICS: inhaled corticosteroid; FEV1: forced expiratory volume in one second; % pred: per cent predicted; PC20 histamine: airway responsiveness to histamine. #: beclomethasone equivalent.