Repeatability of airway resistance measured by the interrupter technique (Rint)
| Within-occasion | Between-occasion | |||
|---|---|---|---|---|
| All groups (n=85) | Controls (n=72) | Coughers (n=57) | Wheezers (n=95) | |
| CV=coefficient of variation; ICC= intraclass correlation coefficient. | ||||
| e*Age at first visit. | ||||
| e†Mean difference for (a) within occasion = pre – post placebo; (b) between occasion = visit 1 – visit 2. | ||||
| Age (years) | ||||
| Median (range) | 4.8 (2.0–9.9) | 6.2 (2.2–9.8)* | 4.7 (2.0–9.4)* | 4.4 (2.0–9.5)* |
| Mean difference† | ||||
| % expected | –0.4% | 4.3% | 4.4% | 5.2% |
| 95% CI | (–0.1 to +0.1) | (+0.6 to +8.0) | (–2.1 to +11) | (–0.1 to +10.5) |
| p value | 0.46 | 0.02 | 0.18 | 0.05 |
| CV | 6.5% | 11% | 16% | 15% |
| ICC | 0.97 | 0.75 | 0.56 | 0.66 |
| Limits of agreement | ||||
| % expected | 20% | 32% | 49% | 52% |
| z scores | 0.87 | 1.38 | 1.88 | 1.92 |
| Absolute values (kPa/l.s) | 0.17 | 0.23 | 0.38 | 0.44 |