Table 1.
Characteristics of all chronic obstructive pulmonary disease study patients and patients having three exacerbations or more in the year prior to cohort entry
| Variables | All patients, n = 36 492 | Patients with ≥3 exacerbations in year prior to cohort entry, n = 3040 |
|---|---|---|
| Male (%) | 22 430 (61.5) | 1915 (63.0) |
| Age at cohort entry (years), mean ± SD | 73.1 ± 8.5 | 73.0 ± 8.0 |
| Income, n (%) | ||
| Poor to average | 22 828 (62.6) | 1803 (59.3) |
| Other | 13 664 (37.4) | 1237 (40.7) |
| Follow-up (years), mean ± SD | 2.4 ± 1.9 | 1.5 ± 1.6 |
| Year of cohort entry, n (%) | ||
| 1996 | 10 461 (26.7) | 903 (29.7) |
| 1997 | 7 116 (19.5) | 561 (18.5) |
| 1998 | 6 991 (19.2) | 574 (18.9) |
| 1999 | 6 092 (16.7) | 497 (16.4) |
| 2000 | 5 832 (16.0) | 505 (16.6) |
| ≥1 episode(s) of treatment during follow-up, n (%) | ||
| Theophylline | 8 371 (22.9) | 865 (28.5) |
| ICS | 23 262 (63.7) | 1736 (57.1) |
| LABA | 3 015 (8.3) | 239 (7.9) |
| LABA plus ICS | 5 738 (15.7) | 492 (16.2) |
| Theophylline plus ICS | 9 200 (25.2) | 1117 (36.7) |
| In the year prior to cohort entry | ||
| COC index, mean ± SD | 0.45 ± 0.29 | 0.43 ± 0.26 |
| Comorbidity score, mean ± SD | 8.9 ± 4.1 | 11.4 ± 3.8 |
| Prescriptions of oral corticosteroids, n (%) | ||
| 0 | 22 667 (62.1) | 109 (3.6) |
| 1 | 7 047 (19.3) | 197 (6.5) |
| 2 | 2 939 (8.1) | 365 (12.0) |
| ≥3 | 3 842 (10.5) | 2368 (77.9) |
| Emergency department visits COPD, n (%) | ||
| 0 | 25 895 (71.0) | 902 (29.7) |
| 1 | 7 814 (21.4) | 848 (27.9) |
| ≥2 | 2 783 (7.6) | 1290 (42.4) |
| Hospitalizations for COPD, n (%) | ||
| 0 | 29 468 (80.8) | 1376 (45.3) |
| ≥1 | 7 024 (19.2) | 1664 (54.7) |
| In the 3 months prior to cohort entry | ||
| ≥1 visit(s) to a respiratory physician, n (%) | 6 311 (17.3) | 911 (30.0) |
| Number of filled prescriptions of antibiotics for COPD, mean ± SD | 0.5 ± 0.9 | 1.1 ± 1.3 |
| Number of doses of SABA per day, mean ± SD | 3.2 ± 2.2 | 4.3 ± 2.7 |
| Number of doses of ipratropium bromide per day, mean ± SD | 2.1 ± 2.3 | 3.4 ± 2.8 |
COPD, Chronic obstructive pulmonary disease; COC, continuity of care; ICS, inhaled corticosteroids; LABA, long-acting β2-agonists; SABA, short-acting β2>-agonists.