Obstructive group

(%FEV₁ ≤ 70%, n = 22)

Non-obstructive group

(%FEV₁ > 70%, n = 33)

Changed rates (Δ) (%)

COPD

(C-group, n = 22)

Tiotropium

Smoker

(S-group, n = 10)

Tiotropium

Non-smoker

(N-group, n = 23)

Control

p value

Mean ± SD

Mean ± SD

Mean ± SD

C-g vs S-g

C-g vs N-g

S-g vs N-g

ΔVC (%)

−6.0 ± 15.0

21.9 ± 4.2

−11.0 ± 12.0

0.0876

0.2332

0.0102

ΔFEV₁ (%)

5.0 ± 19.0

16.8 ± 4.0

−10.0 ± 14.0

0.3979

0.1513

0.0004

ΔVC% (predicted, %)

−5.0 ± 14.0

77.5 ± 18.1

−11.0 ± 12.0

0.0785

0.1539

0.0101

ΔFEV1/FVC (%)

45.0 ± 16.0

56.9 ± 8.4

29.0 ± 12.0

0.4068

0.1355

0.0004