Demographics and characteristics of the study population
| Characteristic | Formoterol | Salbutamol | Total |
| Subjects n | 9064 | 9060 | 18124 |
| Gender % female | 57 | 58 | 57 |
| Race Caucasian/Oriental/Other n | 6915/1438/711 | 6902/1428/730 | 13817/2866/1441 |
| Age yrs mean (range) | 39 (5–91) | 39 (4–91) | 39 (4–91) |
| Age groups | |||
| Children ≤11 yrs | 847 | 849 | 1696 (9%) |
| Adolescents 12–17 yrs | 790 | 804 | 1594 (9%) |
| Adults 18–64 yrs | 6526 | 6468 | 12994 (72%) |
| Elderly ≥65 yrs | 901 | 939 | 1840 (10%) |
| Severity judged by asthma medication levels# | |||
| Intermittent | 1427 | 1396 | 2823 (16%) |
| Mild | 3178 | 3135 | 6313 (35%) |
| Moderate | 3127 | 3154 | 6281 (35%) |
| Severe | 1332 | 1375 | 2707 (15%) |
| Maintenance treatment at entry | |||
| ICS | 6877 | 6907 | 13784 (76%) |
| LABA | 2782 | 2905 | 5687 (31%) |
| Leukotriene modifiers | 830 | 843 | 1673 (9%) |
| Cromones | 220 | 204 | 424 (2%) |
| Xanthines, oral β2‐agonists | 1131 | 1234 | 2365 (13%) |
| Oral corticosteroids | 391 | 389 | 780 (4%) |
| Others | 921 | 940 | 1861 (10%) |
#: Intermittent: no maintenance treatment
mild: inhaled corticosteroids (ICS) <500 µg·day−1 (<400 µg·day−1 in children) or a regular long-acting β2‐agonist (LABA), cromone, theophylline or leukotriene modifier
moderate: ICS alone any dose ≥500 µg·day−1 (≥400 µg·day−1 in children), or ICS 500–800 µg·day−1 (400–800 µg·day−1 in children) in combination with LABA, theophylline or leukotriene modifier
severe: ICS >800 µg·day−1 in combination with LABA, theophylline, leukotriene modifier, or oral corticosteroids 16