Background
Exercise training improves exercise tolerance in chronic obstructive pulmonary disease (COPD). Tiotropium 18 μg once daily induces sustained bronchodilation throughout the day and reduces hyperinflation, one of the pathophysiological factors contributing to exertional dyspnea in COPD patients.
Aim
To determine whether tiotropium enhances the effects of exercise training in patients with COPD.
Design
Multicenter, 25 week randomized, double-blind, placebo-controlled, parallel-group study.
Setting
Twelve Italian Pulmonary Units practicing pulmonary rehabilitation.
Patients and intervention
Two hundred thirty four COPD patients (196 males; mean age: 67.4 ± 7.6; forced expiratory volume at 1 second (FEV1): 41.4 ± 13.0% predicted) were randomised to tiotropium 18 μg or placebo inhalation capsules taken once daily. Both groups underwent a 8 week pulmonary rehabilitation program (PR) consisting of 3 exercise training session per week.
Measurements
Baseline, at the end of PR and after 12 weeks, patients completed pulmonary function testing, six minute walking test (6MWT), the Baseline and Transition Dyspnea Index (BDI and TDI), and the St. George’s Respiratory Questionnaire (SGRQ).
Results
Relative to placebo, tiotropium had larger trough and post-study drug FEV1 responses on all test days. At the end of and 12 weeks following PR, patients on tiotropium showed no statistically significant differences in 6MWT compared to patients on placebo. Compared to the period immediately prior to PR, the mean improvement in 6MWT was only 29.7 meters (7.1%) for the combined cohort. Mean TDI focal scores at the end of PR were 3.60 for tiotropium and 2.25 for placebo (p < 0.01). At 12 weeks after PR, TDI focal scores were 2.71 for tiotropium and 2.11 for placebo (p = 0.16). Reduction in all four SGRQ component scores, indicating an improvement in health-related quality of life, was observed for the tiotropium group over the duration of the study compared to placebo but the differences were not statistically significant. During the study period, there were fewer exacerbations and exacerbation days in the tiotropium group.
Conclusion
Although significant improvements were observed with perceived dyspnea, compared to placebo, the addition of tiotropium to pulmonary rehabilitation did not improve the 6MWT.