Figures
- FIGURE 1
Study flowchart. ERS: European Respiratory Society.
- FIGURE 2
Comparisons of the z-scores of oscillometric parameters between different groups. R5: resistance at 5 Hz; R20: resistance at 20 Hz; X5: reactance at 5 Hz; fres: resonant frequency; AX: reactance area; ILD: interstitial lung disease; UAO: upper airway obstruction; ULN: upper limit of normal (1.645); LLN: lower limit of normal (−1.645). ns: nonsignificant between-group difference (p>0.05); other between-group differences without this notation were all significant (p<0.05).
- FIGURE 3
Equations of the z-scores of oscillometric parameters predicted by the forced expiratory volume in 1 s (FEV1) z-score. The solid lines represent medians and the shaded areas 95% confidence intervals. R5: resistance at 5 Hz; R20: resistance at 20 Hz; X5: reactance at 5 Hz; ILD: interstitial lung disease; UAO: upper airway obstruction.
- FIGURE 4
Diagnostic performances of oscillometric and spirometric parameters in diagnosing respiratory diseases (interstitial lung disease (ILD)+asthma+COPD+bronchiectasis+upper airway obstruction (UAO) versus healthy) and airway obstructive diseases (asthma+COPD+bronchiectasis+UAO versus healthy+ILD). R5: resistance at 5 Hz; AX: reactance area; fres: resonant frequency; X5: reactance at 5 Hz; R20: resistance at 20 Hz; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity.
Tables
- TABLE 1
Anthropometrics and spirometric parameters of the analysed population
Healthy ILD Asthma COPD Bronchiectasis UAO Subjects, N 567 274 781 688 109 40 Females, n (%) 300 (52.9) 124 (45.3) 441 (56.5) 58 (8.4) 66 (60.6) 19 (47.5) Age, years 38.3±14.3 57.4±11.6 45.9±12.9 63.2±8.6 52.9±11.1 54.5±14.9 Height, cm 164.3±8.3 161.6±8.0 162.2±8.2 165.2±7.0 160.0±8.4 160.7±7.5 Weight, kg 62.9±11.1 64.8±10.9 63.7±12.5 62.7±11.5 58.0±12.1 61.7±10.7 BMI, kg·m−2 23.2±3.1 24.7±3.3 24.1±3.7 22.9±3.6 22.5±3.7 23.8±3.3 FEV1, L# 3.32±0.72 2.15±0.64 2.39±0.83 1.5±0.64 1.93±0.74 2.11±0.85 FEV1 z-score# 0.291±0.914 −1.766±1.664 −1.784±1.902 −4.12±1.796 −2.506±1.942 −2.034±2.34 FVC, L# 3.96±0.87 2.71±0.84 3.52±0.95 3.02±0.80 2.84±0.86 3.22±0.84 FVC z-score# 0.310±0.978 −1.800±1.753 −0.225±1.442 −1.517±1.690 −1.363±1.482 −0.407±1.526 FEV1/FVC# 83.8±5.5 80.1±8.7 67.2±13.0 48.5±12.8 67.2±14.1 64.2±16.0 FEV1/FVC z-score# −0.047±0.791 0.01±1.507 −2.572±2.16 −4.849±2.047 −2.329±2.382 −2.882±2.948 MMEF, L·s−1¶ 3.45±1.06 1.89±0.88 1.63±0.97 0.59±0.39 1.21±0.89 1.76±0.82 MMEF z-score¶ 0.153±0.993 −0.904±1.347 −1.917±1.172 −2.901±0.552 −2.094±1.304 −1.399±1.067 PEF, L·s−1# 8.02±1.93 5.12±2.19 6.08±1.98 4.00±2.21 7.03±1.94 4.08±2.27 PEF z-score# 0.378±0.995 −1.212±1.537 −2.653±1.311 −0.233±1.349 −1.623±1.464 −2.658±1.661 Data are presented as mean±sd unless otherwise stated. ILD: interstitial lung disease; UAO: upper airway obstruction; BMI: body mass index; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; MMEF: maximum mid-expiratory flow; PEF: peak expiratory flow. #: 11 data were missing from this analysis; ¶: 177 data were missing from this analysis.
- 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.
- TABLE 3
Comparisons of the diagnostic values between R5 and spirometric parameters
AUC (95% CI) p-value Cut-off Sensitivity Specificity Respiratory diseases R5 z-score 0.807 (0.790–0.824) <0.01 >1.426 62.4% 90.3% FEV1 z-score 0.900 (0.888–0.912) <0.01 ≤ −1.112 74.0% 95.4% FEV1/FVC z-score 0.861 (0.847–0.875) <0.01 ≤ −1.410 70.5% 97.4% Obstructive airway diseases R5 z-score 0.788 (0.770–0.806) <0.01 >1.426 66.7% 81.5% FEV1 z-score 0.820 (0.803–0.837) <0.01 ≤ −1.069 76.2% 75.2% FEV1/FVC z-score 0.922 (0.912–0.933) <0.01 ≤ −1.401 80.72% 94.5% UAO R20 z-score 0.895 (0.852–0.938) <0.01 >2.300 87.5% 79.0% FEV1 z-score 0.509 (0.420–0.598) 0.84 ≤ −0.230 82.1% 26.6% 0.557 (0.473–0.640) 0.18 ≤ −0.595 87.2% 32.2% PEF z-score 0.728 (0.657–0.799) <0.01 ≤−0.835 89.47% 47.87% AUC: area under the curve; respiratory diseases: interstitial lung disease+asthma+COPD+bronchiectasis+upper airway obstruction (UAO) versus healthy; R5: resistance at 5 Hz; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; obstructive airway diseases: asthma+COPD+bronchiectasis+UAO versus healthy+ILD; R20: resistance at 20 Hz; PEF: peak expiratory flow.
- TABLE 4
z-scores of oscillometric parameters corresponded to forced expiratory volume in 1 s (FEV1) z-score −2.5 and −4
R5 z-score R20 z-score R5−R20 z-score X5 z-score FEV1 z-score −2.5 −4 −2.5 −4 −2.5 −4 −2.5 −4 Healthy 1.024 1.506 0.656 0.925 1.787 2.448 −2.129 −3.162 ILD 2.859 4.682 1.475 2.162 3.089 5.02 −5.2 −8.558 Asthma 2.374 4.006 1.196 1.518 2.737 5.367 −3.606 −8.815 COPD 1.318 1.954 0.35 0.479 2.072 3.223 −3.146 −4.374 Bronchiectasis 2.022 3.624 0.632 1.129 2.608 4.573 −4.683 −8.185 UAO 7.932 10.188 3.645 4.055 8.209 11.52 −15.639 −21.406 Average of asthma+COPD+bronchiectasis 2.418 4.104 2.811 4.987 −4.496 −8.519 R5: resistance at 5 Hz; R20: resistance at 20 Hz; X5: reactance at 5 Hz; ILD: interstitial lung disease; UAO: upper airway obstruction.
Supplementary Material
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Supplementary material 00080-2022.SUPPLEMENT
