Table 1.

Baseline characteristics of the study population (31 December 2003)

	All (n = 19,752)	Infrequent exacerbators (n = 13,835)	Frequent exacerbators (n = 5917)	Severe exacerbators (n = 9853)
Sex
Male	8452 (42.8%)	5848 (42.3%)	2604 (44.0%)	4379 (44.4%)
Female	11,300 (57.2%)	7987 (57.7%)	3313 (56.0%)	5474 (55.6%)
Age (years)
Median (IQR)	71 (64–77)	70 (63–77)	71 (65–77)	72 (66–78)
55–69 years	8877 (44.9%)	6366 (46.0%)	2511 (42.4%)	3688 (37.4%)
70–79 years	7686 (38.9%)	5194 (37.5%)	2492 (42.1%)	4259 (43.2%)
80 + years	3189 (16.1%)	2275 (16.4%)	914 (15.4%)	1906 (19.3%)
Previous exacerbations
No	8595 (43.5%)	7098 (51.3%)	1497 (25.3%)	3729 (37.8%)
Yes	11,157 (56.5%)	6737 (48.7%)	4420 (74.7%)	6124 (62.2%)
Drug classes used
1	3574 (18.1%)	3058 (22.1%)	516 (8.7%)	1287 (13.1%)
2	5552 (28.1%)	4231 (30.6%)	1321 (22.3%)	2244 (22.8%)
3+	10,561 (53.5%)	6483 (46.9%)	4078 (68.9%)	6284 (63.8%)
Medication
ICS	10,814 (54.7%)	7254 (52.4%)	3560 (60.2%)	5330 (54.1%)
LAMA	7007 (35.5%)	4306 (31.1%)	2701 (45.6%)	4286 (43.5%)
LABA	6512 (33.0%)	4181 (30.2%)	2331 (39.4%)	3572 (36.3%)
SABA	12,906 (65.3%)	8837 (63.9%)	4069 (68.8%)	6621 (67.2%)
SAMA	1254 (6.3%)	717 (5.2%)	537 (9.1%)	887 (9.0%)
Combination (SABA + SAMA)	8442 (42.7%)	5100 (36.9%)	3342 (56.5%)	5499 (55.8%)
Combination (LABA+ICS)	6940 (35.1%)	4484 (32.4%)	2456 (41.5%)	3663 (37.2%)

Individuals are classified according to rate and severity of exacerbations in year 2003

Non-exacerbators (0 exacerbations in the given year)

Infrequent exacerbators (1 exacerbation in the given year)

Frequent exacerbators (≥2 exacerbations in the given year)

Severe exacerbators (≥1 hospitalization with COPD in the given year)

ICS inhaled corticosteroids, LAMA long-acting muscarinic antagonists, LABA long-acting beta-agonists, SAMA short-acting muscarinic antagonists, SABA short-acting beta-agonists