Table 4– Multivariate regression analysis of the association between change in (Δ) provocative concentration of methacholine causing a 20% fall in forced expiratory volume in 1 s (PC₂₀) between 6- and 30-month treatment, and the changes in clinical and inflammatory variables in sputum and bronchial biopsies

	Methacholine Δlog₂ PC₂₀	p-value
Current smoker	-1.96 (-3.35– -0.58)	0.006
Age yrs	-0.05 (-0.13–0.04)	0.259
Female sex	0.11 (-2.48–2.69)	0.934
Treatment group
Fluticasone/salmeterol	-0.94 (-2.77–0.90)	0.310
Fluticasone
6 months	-2.43 (-4.14– -0.73)	0.006
30 months	-0.12 (-1.80–1.56)	0.887
ΔRV/TLC % pred	-0.04 (-0.08– -0.07)	0.021
Δ sputum macrophages ×10⁴ cells·mL^−1#,¶	-1.72 (-2.78– -0.68)	0.002

Data are presented as β (95% CI), unless otherwise stated. Bold indicates statistically significant values. RV: residual volume; TLC: total lung capacity; % pred: % predicted. ^#: log transformed; ^¶: β -1.56 (95% CI -2.69– -0.42) for sputum lymphocytes (p=0.008), -1.33 (95% CI -2.40– -0.27) for sputum neutrophils (p=0.015) and -1.11 (95% CI -2.30–0.08) for total number of cells in sputum (p=0.066).