Annual mean variation of FEV1
| Diagnose | Year 1 | Year 2 | Year 3 | |
| FEV1 (ml) | 1023 | 1083 | 1073 | 1053 |
| Δ ml | --------------------- | 60 | 50 | 30 |
| Reduction of FEV1 (ml/year) | ---------------------- | ---------------------- | - 10 | - 20 |
Annual average FEV1 after BD in the three years of treatment