FEV1 <50% pred | FEV1 ≥50% pred | |||||
Blood eosinophils <0.34×109 cells·L−1 | Blood eosinophils ≥0.34×109 cells·L−1 | p-value | Blood eosinophils <0.34×109 cells·L−1 | Blood eosinophils ≥0.34×109 cells·L−1 | p-value | |
Subjects n | 521 | 122 | 5646 | 891 | ||
Male | 261 (50) | 91 (75) | <0.001 | 2700 (48) | 531 (60) | <0.001 |
Age years | 71 (64–77) | 71 (66–78) | 0.32 | 63 (53–71) | 64 (55–73) | 0.02 |
Current smokers | 224 (43) | 49 (40) | 0.57 | 2045 (36) | 367 (41) | 0.004 |
Pack-years of smoking# | 40 (26–55) | 43 (28–63) | 0.05 | 28 (15–42) | 30 (18–45) | <0.001 |
≥10 pack-years of smoking# | 445 (85) | 108 (89) | 0.37 | 3641 (64) | 638 (72) | <0.001 |
Body mass index kg·m−2 | 25.5 (22.6–28.5) | 25.8 (22.9–29.0) | 0.24 | 24.9 (22.7–27.6) | 25.3 (23.1–28.1) | 0.003 |
Low level of education¶ | 346 (66) | 80 (66) | 0.86 | 2977 (53) | 478 (54) | 0.61 |
FEV1 % predicted | 42 (36–46) | 43 (37–46) | 0.26 | 81 (69–91) | 79 (67–90) | 0.003 |
Users of inhaled corticosteroids+ | 148 (28) | 33 (27) | 0.76 | 250 (4) | 61 (7) | 0.002 |
Ischaemic heart disease prior to baseline | 71 (14) | 33 (27) | <0.001 | 424 (8) | 113 (13) | <0.001 |
Frequency of exacerbations per individual per year during follow-up | 0.59±1.28 | 1.06±1.83 | 0.03 | 0.11±0.50 | 0.12±0.45 | 0.01 |
Number of high biomarkers§ | <0.001 | <0.001 | ||||
0 | 198 (38) | 29 (24) | 3425 (61) | 404 (45) | ||
1 | 161 (31) | 37 (30) | 1408 (25) | 274 (31) | ||
2 | 118 (23) | 31 (25) | 610 (11) | 145 (16) | ||
3 | 44 (8) | 25 (21) | 203 (4) | 68 (8) |
Data are presented as n (%), median (interquartile range) or mean±sd, unless otherwise stated. n=7180. #: pack-years were calculated for current and former smokers only; ¶: low level of education was <3 years following mandatory primary school; +: recorded up to 1 year prior to baseline; §: defined as C-reactive protein >3 mg·L−1, leukocytes >9×109 cells·L−1 and/or fibrinogen >14 μmol·L−1, as done previously [18, 21].