| Tiotropium (n = 1308) | Combined ipratropium and salbutamol (n = 654) | RR | 95% CI (p value) | |
| Infected exacerbation: number of patients with at least 1 exacerbation | 127 | 86 | 0.74 | 0.62 to 0.87(0.02) |
| COPD-related referrals: number of patients with at least 1 COPD referral | 63 | 50 | 0.63 | 0.51 to 0.77(<0.0001) |
| Inhaled steroids: patients with at least 1 prescription on inhaled steroids | 687 | 409 | 0.84 | 0.77 to 0.92(<0.0001) |
| Salbutamol: patients with at least 1 prescription on salbutamol | 563 | 183 | 1.54 | 1.35 to 1.76(<0.0001) |