Background: Chronic obstructive pulmonary disease (COPD) and asthma have different diagnostic criteria and treatment paradigms. Both are common and can occur in the same patient. We sought to determine the spirometric effects of tiotropium in COPD patients with concomitant asthma.
Methods: A 12-week randomized, double-blind, placebo-controlled, parallel group trial with tiotropium 18 mcg daily was performed. Patients continued usual respiratory medications except for inhaled anticholinergics.
Inclusion criteria: Physician diagnosis of COPD and asthma, age >or= 40 years, smoking >10 pack years, post-bronchodilator forced expiratory volume in 1s (FEV(1))<80% predicted, FEV(1)/forced vital capacity (FVC)<70%, >or= 12%, and >or= 200 ml increase in FEV(1) following inhaled bronchodilator, treatment with inhaled steroids >or= 1 year. Spirometry was measured serially for 6h on days 1, 29 and 85.
Results: Four hundred and seventy-two patients were randomized. Baseline characteristics were balanced. Mean age=59.6 years, 61.4% were men, and FEV(1)=1.55l (53.0% predicted). Improvements at 12 weeks with tiotropium were observed for the primary endpoint FEV(1) area under the curve (AUC) from 0 to 6h (difference=186+/-24 ml, p<0.001) and for morning pre-dose FEV(1) (difference=98+/-23 ml, p<0.001). Significant differences in favor of tiotropium were observed for pre-dose FVC (difference=128+/-34 ml, p<0.001) and FVC AUC 0-6h (difference=232+/-35 ml, p<0.001). Compared to baseline, the mean weekly number of daily puffs of prn salbutamol was reduced by 0.05+/-0.12 puffs/day in the placebo group and by 0.50+/-0.12 puffs/day in the tiotropium group at week 12 (p<0.05).
Conclusions: Patients with COPD and concomitant asthma achieve spirometric improvements with tiotropium along with symptomatic benefit as seen by reduced need for rescue medication.