TABLE 2

Changes in forced expiratory volume in 1 s (FEV₁) and forced vital capacity (FVC) before and after bronchodilator use after withdrawing tiotropium in early chronic obstructive pulmonary disease (COPD)^#

	Placebo	Tiotropium	Difference (tiotropium − placebo)^¶	p-value
Subjects n	126	136
FEV₁ L
Before bronchodilator use
Month 25	1.79±0.02	1.89±0.02	0.10 (0.04–0.16)	0.0018
Month 36	1.71±0.04	1.78±0.04	0.07 (−0.02–0.15)	0.12
Month 48	1.70±0.03	1.74±0.03	0.04 (−0.03–0.11)	0.23
Month 60	1.69±0.04	1.77±0.04	0.08 (−0.04–0.19)	0.18
After bronchodilator use
Month 25	1.92±0.02	1.99±0.02	0.07 (0.01–0.13)	0.0145
Month 36	1.81±0.04	1.85±0.04	0.04 (−0.04–0.12)	0.31
Month 48	1.84±0.03	1.85±0.03	0.008 (−0.06–0.07)	0.79
Month 60	1.80±0.03	1.84±0.03	0.04 (−0.05–0.13)	0.36
FVC L
Before bronchodilator use
Month 25	3.02±0.03	3.10±0.04	0.08 (−0.01–0.18)	0.09
Month 36	2.93±0.06	2.99±0.06	0.06 (−0.08–0.19)	0.41
Month 48	2.91±0.05	2.93±0.05	0.03 (−0.09–0.14)	0.67
Month 60	2.89±0.07	3.01±0.07	0.12 (−0.07–0.30)	0.21
After bronchodilator use
Month 25	3.13±0.03	3.17±0.03	0.04 (−0.04–0.12)	0.36
Month 36	3.03±0.05	3.06±0.05	0.02 (−0.84–0.13)	0.66
Month 48	3.10±0.05	3.07±0.05	−0.02 (−0.13–0.08)	0.67
Month 60	3.00±0.06	3.10±0.06	0.09 (−0.06–0.26)	0.23

Data are presented as mean±se, unless otherwise stated. ^#: values were measured from month 36 until the end of the study (follow-up from 36 to 60 months after withdrawing tiotropium in early COPD). Multiple linear regression was adopted for each follow-up. For each follow-up visit, the measured value was the dependent variable, and covariates included the individual baseline value, smoking status across the whole follow-up, bronchiectasis status, treatment allocation and participating centre as covariates; ^¶: the difference was calculated as the value in the tiotropium group minus the value in the placebo group.