Table 3

Change in lung function, as measured every 3 months, among patients with COPD according to disease severity (GOLD)

Spirometric variable	Visit (months)	GOLD II	GOLD III	GOLD IV	p Values
Spirometric variable	Visit (months)	GOLD II	GOLD III	GOLD IV	GOLD II vs GOLD III	GOLD II vs GOLD IV	GOLD III vs GOLD IV
Post-bronchodilator FEV₁ change (litres)	0	0.16 (0.17)	0.10 (0.13)	0.05 (0.08)	<0.001	<0.001	<0.001
	3	0.15 (0.16)	0.11 (0.13)	0.06 (0.09)	<0.001	<0.001	<0.001
	6	0.16 (0.17)	0.11 (0.12)	0.07 (0.10)	<0.001	<0.001	<0.001
	12	0.16 (0.16)	0.10 (0.12)	0.06 (0.09)	<0.001	<0.001	<0.001
Post-bronchodilator FVC change (litres)	0	0.25 (0.33)	0.25 (0.35)	0.25 (0.32)	0.983	0.865	0.877
	3	0.25 (0.32)	0.25 (0.32)	0.26 (0.30)	0.737	0.733	0.911
	6	0.24 (0.33)	0.24 (0.30)	0.24 (0.32)	0.945	0.730	0.700
	12	0.24 (0.31)	0.22 (0.32)	0.19 (0.27)	0.359	0.037	0.148
Post-bronchodilator FEV₁/FVC change (%)	0	0.94 (4.39)	0.04 (4.11)	–1.30 (4.47)	<0.001	<0.001	<0.001
	3	0.74 (3.97)	0.29 (3.94)	–0.88 (5.08)	0.031	<0.001	<0.001
	6	1.10 (4.66)	0.40 (3.88)	–0.51 (4.99)	0.002	<0.001	0.006
	12	1.05 (4.17)	0.52 (3.91)	0.11 (4.54)	0.011	0.002	0.180

Data are given as mean (SD).
COPD, chronic obstructive pulmonary disease; FEV₁, forced expiratory volume in 1 s; FVC, forced vital capacity; GOLD, Global initiative for chronic Obstructive Lung Disease.