The effect of tiotropium on hyperinflation and exercise capacity in chronic obstructive pulmonary disease.

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitation, which results in the progressive development of dyspnea and exercise limitation.

OBJECTIVE AND METHODS

To compare the effect of tiotropium with placebo on forced vital capacity (FVC) in patients with moderate-to-severe COPD and lung hyperinflation, using exercise endurance, dyspnea and health-related quality of life (HRQoL) as secondary endpoints. One hundred patients were randomized to receive either tiotropium 18 mug once daily or placebo for 12 weeks.

RESULTS

Trough (predose) FVC was significantly improved with tiotropium compared to placebo on day 42 (0.27 +/- 0.08 liters) and 84 (0.20 +/- 0.08 liters; p < 0.05 for both). Trough inspiratory capacity (IC) was also significantly improved with tiotropium compared to placebo on day 42 (0.16 +/- 0.07 liters) and 84 (0.15 +/- 0.07 liters; p < 0.05 for both). Tiotropium increased the mean distance walked during the shuttle walking test by 33 +/- 12 (day 42) and 36 +/- 14 m (day 84) compared to placebo (p < 0.05 for both). On day 84, 59% of the patients in the tiotropium group and 35% of the patients in the placebo group had significant and clinically meaningful improvements in the St. George's Respiratory Questionnaire total score (p < 0.05). Numerical decreases in the focal score in the Transition Dyspnea Index in patients receiving tiotropium versus placebo suggest that tiotropium also improved dyspnea during activities of daily living.

CONCLUSION

Tiotropium 18 mug once daily reduced hyperinflation with consequent improvements in walking distance and HRQoL in patients with COPD and lung hyperinflation.