Table 5.

Regression models for lung function, exercise capacity and symptoms in all subjects

A. Linear regression for FEV1 (L)
	Exp−856		E/I MLA		RVC856-950
Independent variables	β*	p-value	β*	p-value	β*	p-value
% emphysema (Insp−950)	−0.11	< 0.0001	−0.31	< 0.0001	−0.29	< 0.0001
Gas Trapping variable†	−0.45	< 0.0001	−0.30	< 0.0001	−0.30	< 0.0001
Model fit statistics
R2	0.67		0.68		0.68
B. Linear regression for FEV1/FVC
	Exp−856		E/I MLA		RVC856-950
Independent variables	β*	p-value	β*	p-value	β*	p-value
% emphysema (Insp−950)	−0.03	< 0.0001	−0.09	< 0.0001	−0.10	< 0.0001
Gas Trapping variable†	−0.10	< 0.0001	−0.06	< 0.0001	−0.03	< 0.0001
Model fit statistics
R2	0.73		0.70		0.64
C. Linear regression for FEF25-75
	Exp−856		E/I MLA		RVC856-950
Independent variables	β*	p-value	β*	p-value	β*	p-value
% emphysema (Insp−950)	0.0002	0.99	−0.29	< 0.0001	−0.38	< 0.0001
Gas Trapping variable†	−0.68	< 0.0001	−0.51	< 0.0001	−0.24	< 0.0001
Model fit statistics
R2	0.50		0.52		0.45
D. Linear regression for 6-minute walk distance (ft).
	Exp−856		E/I MLA		RVC856-950
Independent variables	β*	p-value	β*	p-value	β*	p-value
% emphysema (Insp−950)	−47.8	< 0.0001	−46.3	< 0.0001	−37.3	< 0.0001
Gas Trapping variable†	−3.7	0.6	−22.0	< 0.0001	−51.8	< 0.0001
Model fit statistics
R2	0.44		0.44		0.45
E. Linear regression for SGRQ Total score.
	Exp−856		E/I MLA		RVC856-950
Independent variables	β*	p-value	β*	p-value	β*	p-value
% emphysema (Insp−950)	1.3	0.0004	2.8	< 0.0001	2.7	< 0.0001
Gas Trapping variable†	3.2	< 0.0001	1.9	< 0.0001	1.7	< 0.0001
Model fit statistics
R2	0.42		0.42		0.42

All models are adjusted for age, sex, race, clinical center, current smoking status, pack-years of smoking, height, weight, Siemens 64 scanner. Models for 6-minute walk distance (D) and SGRQ score (E) were additionally adjusted for FEV1% predicted.

*Independent variables standardized to mean = 0 and SD = 1. β = change in dependent variable, e.g. FEV₁ (L), for each SD change in independent variable.

†Either Exp₋₈₅₆, E/I mean lung attenuation ratio, or RVC_856-950.