Table 1.
Comparison of baseline characteristics of the TRAIL cohort, between those who experience 0, 1–2 and 3 + exacerbations
| 0 (n = 849) | 1–2 (n = 182) | 3 + (n = 40) | p-value | |
|---|---|---|---|---|
| Sex, n women (%) | 506 (60) | 114 (63) | 29 (73) | 0.228 |
| Age | 35 (14) | 50 (15) | 54 (13) | < 0.001 |
| Decade of inclusion | ||||
| 1974–1979 | 115 (14) | 40 (22) | 9 (23) | 0.013 |
| 1980–1989 | 641 (76) | 131 (72) | 27 (68) | |
| 1990 | 93 (11) | 11 (6) | 4 (10) | |
| Adultonseta, n (%) | 587 (69) | 147 (81) | 33 (83) | 0.002 |
| Ever smokerb, n (%) | 283 (33) | 74 (41) | 22 (55) | 0.006 |
| Pack-yearsc | 9.7 (8.7) | 15 (9.5) | 16 (15) | < 0.001 |
| Previous severe exacerbation, n (%) | 136 (16) | 18 (10) | 6 (15) | 0.100 |
| Daily symptoms, n (%) | 271 (32) | 98 (54) | 29 (73) | < 0.001 |
| Daily use of β2-agonist (> 2 puffs), n (%) | 399 (47) | 120 (66) | 32 (80) | < 0.001 |
| High dose ICS or any dose OCS, n (%) | 184 (22) | 46 (25) | 14 (35) | 0.096 |
| Lung function | ||||
| FEV1% pred | 86 (17) | 74 (21) | 61 (22) | < 0.001 |
| FVC % pred | 94 (15) | 87 (17) | 78 (16) | < 0.001 |
| FEV1/FVC ratio | 78 (71–82) | 70 (58–77) | 58 (54–73) | < 0.001 |
| BD reversibility, n (%) | ||||
| < 12% | 130 (16) | 25 (15) | 2 (5) | 0.221 |
| ≥ 12% | 688 (84) | 145 (85) | 35 (95) | |
| AHRd |
2.4 (1.7–4.5) |
2.1 (1.3–4.6) |
2.1 (1.00–3.1) |
0.072 |
| Peak flow variability, % | 22 (15–29) | 22 (13–26) | 21 (12–25) | 0.200 |
| Blood eosinophils |
0.34 (0.21–0.57) |
0.38 (0.21–0.57) |
0.45 (0.23–0.54) |
0.534 |
| Total IgE, IU/l |
129 (43–345) |
93 (35–317) |
125 (33–279) |
0.165 |
| Negative skin prick test, n (%) | 326 (38) | 114 (63) | 29 (73) | < 0.001 |
Data are presented as mean (standard deviation) or median interquartile range), unless otherwise stated
AHR airway hyperresponsiveness, BD bronchodilator, FEV1 forced expiratory volume in 1 second, FVC forced vital capacity, ICS inhaled corticosteroids, IU International Unit, OCS oral corticosteroids
aAge ≥ 18 years
bCurrent or ex-smokers
cFor ever smokers
dMissing data on 266