Table 1

Baseline characteristics of the study population

TotalNo ICSLow ICSMedium ICSHigh ICS
No of subjects18 867 (100.0)5687 (30.1)4361 (23.1)4457 (23.6)4362 (23.1)
Demographics
 Age69.6 (62.0–77.0)68.5 (60.3–76.0)69.3 (61–76.8)70.3 (63.4–77.5)70.6 (63.7–77.6)
 Female10 188 (54.0)2691 (47.3)2278 (52.2)2486 (55.8)2732 (62.6)
 BMI, median (IQR)25 (21–29)25 (22–29)25 (22–29)25 (21–29)24 (21–28)
Pulmonary parameters
 FEV1 (%) median (IQR)49 (36–63)57 (44–70)53 (40–66)45 (34–58)40 (29–53)
 FEV1 (%)
 ≥801262 (6.7)620 (10.9)337 (7.7)183 (4.1)122 (2.8)
 50–798101 (42.9)3048 (53.6)2177 (49.9)1664 (37.3)1212 (27.8)
 30–496578 (34.9)1609 (28.3)1399 (32.1)1760 (39.5)1810 (41.5)
 <302926 (15.5)410 (7.2)448 (10.3)850 (19.1)1218 (27.9)
Smoking status
 Current7206 (38.2)2610 (45.9)1732 (39.7)1435 (32.2)1429 (32.8)
 Former10 990 (58.2)2879 (50.6)2442 (56.0)2871 (64.4)2798 (64.1)
 Never671 (3.6)198 (3.5)187 (4.3)151 (3.4)135 (3.1)
Severe COPD exacerbations*
 012 944 (68.6)4626 (81.3)2974 (68.2)2863 (64.2)2481 (56.9)
 13822 (20.3)826 (14.5)952 (21.8)984 (22.1)1060 (24.3)
 ≥22101 (11.1)235 (4.1)435 (10.0)610 (13.7)821 (18.8)
Comorbidity
 All-cause hospitalisation*11 938 (63.3)3414 (60.0)2852 (65.4)2793 (62.7)2879 (66.0)
 Hypertension5010 (26.6)1583 (27.8)1167 (26.8)1189 (26.7)1071 (24.6)
 Atrial fibrillation2459 (13.0)773 (13.6)595 (13.6)589 (13.2)502 (11.5)
 Myocardial infarction949 (5.0)290 (5.1)219 (5.0)206 (4.6)234 (5.4)
 Heart failure2774 (14.7)865 (15.2)681 (15.6)617 (13.8)611 (14.0)
 Peripheral vascular disease1533 (8.1)525 (9.2)350 (8.0)345 (7.7)313 (7.2)
 Cerebrovascular disease1184 (6.3)384 (6.8)299 (6.9)251 (5.6)250 (5.7)
 Diabetes mellitus2023 (10.7)662 (11.7)489 (11.2)418 (9.4)454 (10.4)
 Renal disease756 (4.0)277 (4.9)185 (4.2)147 (3.3)147 (3.4)
 Asthma2158 (11.4)296 (5.2)501 (11.5)676 (15.2)685 (15.7)
 Bronchiectasi243 (1.3)76 (1.3)54 (1.2)53 (1.2)60 (1.4)
Use of medication*
 LABA or LAMA13 341 (70.7)2941 (51.7)2990 (68.6)3619 (81.2)3791 (86.9)
 Theofylline645 (3.4)43 (0.8)80 (1.8)177 (4.0)345 (7.9)
 Oral corticosteroids7233 (38.3)1074 (18.9)1578 (36.2)2070 (46.4)2511 (57.5)
  • Data are presented as n (%) unless otherwise specified. Further baseline characteristics are available in online supplemental file 2.

  • *12 months prior to study entry.

  • BMI, body mass index; FEV1, forced expiratory volume in 1 s; ICS, inhaled corticosteroids; LABA, long-acting β2-agonis; LAMA, long-acting muscarinic antagonist; MRC, Medical Research Council.