Independent variables | Unstandardised coefficients B (SE) | 95% CI | Standardised coefficients β | Semipartial correlations | p Value |

Postbronchodilator FEV_{1} (% predicted) | −0.09 (0.03) | −0.16 to −0.02 | −0.32 | −0.28 | 0.008 |

Sputum neutrophils AUC (%) | 0.12 (0.05) | 0.01 to 0.22 | 0.26 | 0.28 | 0.03 |

Disease duration (years) | 0.02 (0.04) | −0.07 to 0.10 | 0.05 | 0.04 | 0.70 |

Modified JACS | 0.55 (0.69) | −0.82 to 1.92 | 0.09 | 0.09 | 0.42 |

Dependent variable is RB1 %WA (n=91).

Model R

^{2}=0.27*, adjusted R^{2}=0.23, R=0.52, p=0.001.*Unique variance=0.16; shared variance=0.11.

Model equation: RB1 %WA =66.02–0.09 (postbronchodialator FEV

_{1}% predicted) +0.12 (sputum neutrophils AUC(%)).Standard multiple regression using ‘enter’ method.

Unstandardised coefficients are used to construct a regression equation. Standardised coefficients are used to compare the unique contribution of each independent variable. Semipartial correlation coefficient squared indicates the contribution of the independent variable to the total R

^{2}.AUC, area under the curve per unit time; FEV

_{1}, forced expiratory volume in 1 s; FVC, forced vital capacity; JACS, Juniper Asthma Control Score; RB1, right upper lobe apical segmental bronchus; WA, wall area.