BACKGROUND: Patients with chronic obstructive pulmonary disease (COPD) who smoke have a greater annual rate of decline in forced expiratory volume in 1 s (FEV₁) than those patients who have stopped smoking.
OBJECTIVES: To assess the effect of tiotropium on pre-dose (trough) FEV₁ in patients with COPD followed in Canada.
METHODS: A total of 913 patients were randomly assigned to receive either tiotropium 18 µg once daily (n=608) or placebo (usual care minus inhaled anticholinergics) (n=305) for 48 weeks in the present randomized, double-blind, parallel-group study. The effect of tiotropium on measurements of lung function (FEV₁, FEV₆ and forced vital capacity), symptoms, health-related quality of life (St George's Respiratory Questionnaire) and exacerbations were examined.
RESULTS: Tiotropium improved trough FEV₁ in both current and ex-smokers compared with placebo. Baseline FEV₁ in smokers and ex-smokers was 1.03 L and 0.93 L, respectively (P<0.001). At week 48, the mean difference between the tiotropium and placebo groups was 0.14±0.04 L (P<0.001) in the smoker group and 0.08±0.02 L (P<0.0001) in the ex-smoker group. Tiotropium also significantly improved trough forced vital capacity and FEV₆ compared with placebo throughout the treatment period (P<0.05, for all). Furthermore, tiotropium significantly improved the St George's Respiratory Questionnaire total score compared with placebo at week 48 (40.9 versus 43.7 units, P<0.005).
CONCLUSIONS: Compared with the placebo group, tiotropium provides sustained improvements in lung function in patients with COPD, with improvements for smokers and ex-smokers.