Emphysema distribution and annual changes in pulmonary function in male patients with chronic obstructive pulmonary disease

Table 2 Prognostic factors contributing to annual change in FEV ₁ in multivariate random coefficient model (n = 131)

	Estimate*	95% Confidence interval	p-value
Age, per 1-year increase	0.86	(0.10 to 1.63)	0.028
Height, per increase of 1 cm	0.03	(−1.11 to 1.17)	0.96
Weight, per increase of 1 kg	0.03	(−0.84 to 0.90)	0.95
%FEV₁, per 1% increase	−0.97	(−1.51 to −0.44)	<0.0001
RV/TLC (%)	0.03	(−1.06 to 1.13)	0.95
D_LCO/V_A (mL/min/mmHg/L)	−0.65	(−8.83 to 7.52)	0.88
Continuous smoking, yes/no	−20.90	(−37.24 to −4.57)	0.013
LAV%, per 1% increase	−2.46	(−3.81 to −1.10)	<0.0001
SD-LAV, per 1% increase	3.24	(0.82 to 5.87)	0.016
WA%, per 1% increase	−0.63	(−1.67 to 0.41)	0.23
Proxy for inspiration^†, per increase of 0.1	−1.67	(−7.36 to 4.01)	0.56

Abbreviations: %FEV₁, percent predicted FEV₁; RV/TLC, ratio of residual volume to total lung capacity;
D_LCO/V_A, ratio of diffusing capacity to alveolar ventilation; LAV%, ratio of low attenuation volume to total lung volume; SD-LAV, standard deviation of LAV% values in 10 partitions with equal volumes;
WA%, wall area percent in right apical bronchus.
^†Proxy for inspiration was defined as the ratio of CT-derived total lung volume to physiologically measured total lung capacity for estimating inspiration levels during CT scan.
*Regression coefficients for interactions with time, a negative value indicates excess annual decline in FEV_1..

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