Characteristics of the study subjects
| Cases | Controls# | |
| Subjects n | 995 | 5416 |
| Age mean±sd | 73.9±8.5 | 73.9±8.2 |
| Male % | 58.6 | 51.0 |
| Mean days of follow-up until index date | 897 | 921 |
| Prescriptions in the previous 12 months of | ||
| Oral corticosteroids | 26.0 (0.85±2.14) | 8.1 (0.23±1.16) |
| Nasal corticosteroids | 5.4 (0.16±0.90) | 5.8 (0.16±0.90) |
| Inhaled β2‐agonists | 74.6 (4.98±5.55) | 52.7 (2.53±3.77) |
| Combined β2/ipratropium | 8.7 (0.58±2.46) | 3.1 (0.17±1.18) |
| Oral β2‐agonists | 6.2 (0.18±1.02) | 5.0 (0.17±0.95) |
| Inhaled ipratropium | 38.4 (2.34±4.31) | 22.1 (1.17±3.00) |
| Anti-allergics | 2.1 (0.09±0.81) | 1.3 (0.05±0.64) |
| Xanthines | 20.7 (1.01±2.62) | 15.7 (0.80±2.38) |
| Antibiotics | 69.1 (1.86±2.11) | 54.5 (1.23±1.73) |
| Use of β‐blockers and/or benzodiazepines¶ | 14.7 | 16.6 |
| Comorbidity in year before index date % | ||
| Cardiac disease | 39.8 | 34.9 |
| Vascular disease | 52.7 | 52.7 |
| Diabetes | 7.2 | 9.0 |
| Psychiatric disease | 31.3 | 32.3 |
| Neurological disorders | 7.1 | 7.1 |
| Rheumatoid arthritis | 1.0 | 0.7 |
Data are presented as percentages (mean±sd) unless otherwise stated
#: to account for case-control matching, all means and percentages for controls were weighted by the inverse of the number of controls in each matched case-control set
¶: any use during the month before index date