Acute bronchodilator responses decline progressively over 4 years in patients with moderate to very severe COPD

Respiratory Research

Table 6 Long-term trends in the proportion of subjects in each treatment arm who achieved a significant bronchodilator response for FEV ₁ , FVC and either FEV ₁ or FVC

	FEV				FVC				FEV or FVC
	Tiotropium		Placebo		Tiotropium		Placebo		Tiotropium		Placebo
Time	N	Proportion	N	Proportion	N	Proportion	N	Proportion	N	Proportion	N	Proportion
1 m	2535	0.42	2416	0.55	2535	0.47	2416	0.62	2535	0.59	2416	0.73
6 m	2515	0.42	2391	0.53	2515	0.44	2391	0.63	2515	0.57	2391	0.72
1 yr	2503	0.39	2382	0.53	2503	0.43	2382	0.63	2503	0.55	2382	0.72
1.5 yr	2380	0.40	2200	0.51	2380	0.43	2200	0.62	2380	0.56	2200	0.71
2 yr	2236	0.39	2040	0.49	2236	0.43	2040	0.60	2236	0.56	2040	0.69
2.5 yr	2132	0.39	1906	0.50	2132	0.42	1906	0.61	2132	0.55	1906	0.70
3 yr	2012	0.36	1792	0.47	2012	0.39	1792	0.59	2012	0.52	1792	0.69
3.5 yr	1894	0.36	1674	0.47	1894	0.41	1674	0.59	1894	0.52	1674	0.68
4 yr	1804	0.35	1599	0.47	1804	0.39	1599	0.56	1804	0.51	1599	0.66
Estimated OR (95% CI) for change in proportion per year*	0.92 (0.90, 0.94)		0.91 (0.89, 0.94)		0.93 (0.91, 0.95)		0.94 (0.92, 0.96)		0.92 (0.90, 0.94)		0.92 (0.90, 0.95)
p-value	<0.0001		<0.0001		<0.0001		<0.0001		<0.0001		<0.0001

*The OR (odds ratio) and its 95% CI were estimated with GEE methods using data starting from 1 m.
FEV: Tiotropium vs. placebo p = 0.79.
FVC: Tiotropium vs. placebo p = 0.60.
FEV or FVC: Tiotropium vs. placebo p = 0.84.

ISSN: 1465-993X