Sensitivity and specificity of selected cut-off points for the parameters evaluated to detect severe exacerbations
| Severe exacerbations | ||
|---|---|---|
| Parameter | Sensitivity % (95% CI) | Specificity % (95% CI) |
| Decrease in PEF (% change vs baseline) | ||
| 30 | 29 (21.6 to 37.0) | 92 (91.5 to 92.0) |
| 20 | 45 (36.0 to 53.6) | 85 (84.8 to 85.7) |
| 15 | 54 (45.6 to 62.8) | 80 (79.6 to 81.0) |
| Decrease in FEV1 (% change vs baseline) | ||
| 30 | 31 (22.3 to 40.5) | 92 (91.0 to 92.0) |
| 20 | 49 (38.8 to 82.0) | 82 (81.3 to 82.7) |
| 15 | 63 (53.7 to 72.6) | 75 (74.0 to 75.7) |
| Increase in SABA use (number of puffs) | ||
| 2 | 4 (2.2 to 5.7) | 97 (96.6 to 97.3) |
| 1 | 4 (2.4 to 5.9) | 96 (95.5 to 96.3) |
| Increase in day symptoms (% change vs baseline) | ||
| 30 | 44 (34.5 to 53.0) | 84.6 (84.6 to 86.0) |
| 20 | 46 (37.0 to 55.6) | 84.9 (83.4 to 84.7) |
| Increase in night symptoms (% change vs baseline) | ||
| 30 | 34 (25.8 to 44.0) | 85 (84.2 to 85.5) |
| 20 | 41 (31.6 to 50.4) | 82 (81.3 to 82.7) |
FEV1, forced expiratory volume in 1 s; PEF, peak expiratory flow; SABA, short-acting β agonist.