Linear regression analyses of the association between age, current smoking and pulmonary function tests and parametric response mapping (PRM)
| PRMfSAD | PRMEmph | PRMPD | |
| Age years# | 0.06** (0.04–0.08) | 0.05** (0.03–0.06) | 0.01* (0.00–0.01) |
| Current smoking¶ | −0.14 (−0.65–0.37) | −0.42 (−0.89–0.05) | 0.24* (0.03–0.44) |
| Pulmonary function tests+ | |||
| FEV1 L | 0.18 (−0.47–0.83) | 0.27 (−0.33–0.86) | −0.17 (−0.43–0.09) |
| FEV1/FVC % | −0.06** (−0.12– −0.01) | −0.05 (−0.10–0.00) | 0.01 (−0.01–0.03) |
| FEF25−75% L·s−1 | −0.28 (−0.62–0.06) | −0.19 (−0.50–0.13) | 0.01 (−0.13–0.15) |
| FEF25−75%/FVC s−1 | −2.29* (−3.84– −0.75) | −1.73** (−3.17– −0.29) | 0.33 (−0.32–0.98) |
| RV L | 3.65** (0.19–7.11) | 1.01 (−0.40–2.42) | −0.44 (−4.72–3.83) |
| TLC L | 0.56** (0.12–0.99) | 0.53** (0.13 –0.93) | −0.11 (−0.29–0.07) |
| RV/TLC % | 0.11* (0.04–0.17) | 0.08** (0.01 –0.14) | 0.01 (−0.02–0.04) |
| TLCOc/VA mmol·min−1·kPa−1·L−1 | −1.97** (−3.55– −0.39) | −1.62** (−3.08– −0.16) | 0.36 (−0.29–1.01) |
| R5−R20 kPa·L−1·s−1 | −6.59** (−12.2– −0.92) | −4.84 (−10.11–0.43) | 0.41 (−0.19–2.76) |
| X5 kPa·L−1·s−1 | 4.92 (−3.51 –13.35) | 5.02 (−2.72–12.76) | −0.62 (−4.04–2.80) |
Data are presented as β (95% CI). PRM values were normalised by natural-logarithmic transformation. PRMfSAD: extent of small airway disease; PRMEmph: extent of emphysema; PRMPD: extent of parenchymal disease; FEV1: forced expiratory volume 1 s; FVC: forced vital capacity; FEF25–75%: forced expiratory flow at 25–75% of FVC; RV: residual volume; TLC: total lung capacity; TLCOc: transfer factor of the lung for carbon monoxide correction for haemoglobin; VA: alveolar volume; R5: resistance at 5 Hz; R20: resistance at 20 Hz; X5: reactance at 5 Hz. #: adjusted for sex and smoking status; ¶: adjusted for sex and age; +: adjusted for age, sex, smoking status and height. Bold indicates statistically significant values. *: p<0.05; **: p<0.01.