TABLE 2.
Intercepts and slopes of the predictive equations of oscillometric parameters (ln z-scores) estimated by the linear mixed model analysis
| ln(5+R5 z-score) | ln(5+R20 z-score) | ln(5+R5−R20 z-score) | ln(42+X5 z-score) | |||||
| Estimate (95% CI) | p-value # | Estimate (95% CI) | p-value # | Estimate (95% CI) | p-value # | Estimate (95% CI) | p-value # | |
| Intercept | ||||||||
| Healthy | 1.67 (1.60–1.73) | <0.001 | 1.66 (1.59–1.72) | <0.001 | 1.76 (1.70–1.82) | <0.001 | 3.73 (3.71–3.75) | <0.001 |
| ILD | 1.68 (1.63–1.74) | 0.555 | 1.64 (1.59–1.69) | 0.463 | 1.71 (1.64–1.77) | 0.081 | 3.71 (3.67–3.75) | 0.095 |
| Asthma | 1.71 (1.68–1.75) | 0.014 | 1.70 (1.67–1.73) | 0.008 | 1.73 (1.69–1.78) | 0.215 | 3.77 (3.74–3.79) | <0.001 |
| COPD | 1.66 (1.61–1.72) | 0.933 | 1.74 (1.69–1.79) | 0.001 | 1.56 (1.49–1.62) | <0.001 | 3.89 (3.85–3.93) | 0.412 |
| Bronchiectasis | 1.61 (1.52–1.70) | 0.182 | 1.59 (1.51–1.67) | 0.091 | 1.65 (1.55–1.75) | 0.027 | 3.78 (3.72–3.85) | 0.095 |
| UAO | 2.29 (2.17–2.42) | <0.001 | 2.08 (1.97–2.19) | <0.001 | 2.21 (2.07–2.35) | <0.001 | 3.68 (3.60–3.77) | 0.007 |
| Slope (against FEV1 z-score) | ||||||||
| Healthy | −0.0514 (−0.0788– −0.0240) |
<0.001 | −0.0309 (−0.0532– −0.0086) |
0.006 | −0.0619 (−0.0956– −0.0282) |
<0.001 | 0.0175 (−0.0039–0.0390) |
0.1081 |
| ILD | −0.0639 (−0.0956– −0.0322) |
0.439 | −0.0159 (−0.0438–0.0121) |
0.292 | −0.1005 (−0.1364– −0.0648) |
0.036 | 0.0214 (−0.0019–0.0447) |
0.743 |
| Asthma | −0.1391 (−0.1661– −0.1121) |
<0.001 | −0.0672 (−0.0909– −0.0435) |
0.003 | −0.1427 (−0.1734– −0.1121) |
<0.001 | 0.0638 (0.0440–0.0837) |
<0.001 |
| COPD | −0.1333 (−0.1610– −0.1056) |
<0.001 | −0.0337 (−0.0579– −0.0095) |
0.821 | −0.1951 (−0.2266– −0.1636) |
<0.001 | 0.0972 (0.0769–0.1175) |
<0.001 |
| Bronchiectasis | −0.1370 (−0.1737– −0.1003) |
<0.001 | −0.0887 (−0.0242– −0.1207) |
0.121 | −0.1532 (−0.1948– −0.1116) |
<0.001 | 0.0657 (0.0389–0.0925) |
<0.001 |
| UAO | −0.1072 (−0.1526– −0.0618) |
0.016 | −0.0309 (−0.0708–0.0089) |
0.998 | −0.1492 (−0.2007– −0.0977) |
0.001 | 0.1646 (0.1316–0.1975) |
<0.001 |
R5: resistance at 5 Hz; R20: resistance at 20 Hz; X5: reactance at 5 Hz; ILD: interstitial lung disease; UAO: upper airway obstruction; FEV1: forced expiratory volume in 1 s. #: p-values of the healthy groups were derived from the comparisons with zero; p-values of disease groups were derived from the comparisons with the healthy group.