Randomised and withdrawn patients
| Tiotropium | Ipratropium | |
| Total randomised and treated | 191 (100) | 97 (100) |
| Withdrawn because of | ||
| Adverse event | 14 (7.3) | 9 (9.3) |
| Lack of efficacy | 2 (1.0) | 0 (0) |
| Protocol violation | 1 (0.5) | 0 (0) |
| Other reasons | 2 (1.0) | 2 (2.1) |
| Completed all test days | 172 (90.1) | 86 (88.7) |
Values are number (%) of patients. No significant differences were seen between the two groups.