Risk of long term mortality in elderly patients, stratified according to the number of prescriptions of ipratropium bromide dispensed during the study period
| No. of prescriptions dispensed | No. of patients |
Mortality rate (per 100 person-years) |
Relative risk for mortality2-150 |
| Asthma | |||
| 0 | 2733 | 8.35 | 1.0 (reference) |
| 1–2 | 1409 | 10.08 | 1.14 (0.99 to 1.31) |
| 3–4 | 763 | 12.37 | 1.17 (0.98 to 1.40) |
| 5–6 | 414 | 12.73 | 1.26 (1.06 to 1.50) |
| 7–8 | 964 | 10.99 | 1.26 (1.06 to 1.51) |
| ⩾9 | 306 | 7.71 | 0.81 (0.61 to 1.08) |
| COPD | |||
| 0 | 7832 | 25.00 | 1.0 (reference) |
| 1–2 | 4952 | 32.73 | 1.20 (1.13 to 1.27) |
| 3–4 | 3426 | 28.87 | 1.07 (1.00 to 1.15) |
| 5–6 | 4074 | 23.58 | 1.02 (0.94 to 1.09) |
| 7–8 | 4319 | 17.12 | 0.91 (0.85 to 0.98) |
| ⩾9 | 1201 | 13.96 | 0.85 (0.76 to 0.94) |
↵2-150 Ajusted for age, sex, comorbidity, length of stay, use of other airway medications and health services (emergency department and physician visits).