Effect of combination treatment on lung volumes and exercise endurance time in COPD

Data comparing two bronchodilators vs. one bronchodilator plus inhaled corticosteroid (ICS) on hyperinflation and exercise endurance in chronic obstructive pulmonary disease (COPD) are scarce, though these therapeutic strategies are widely used in clinical practice.

We performed a randomized, crossover clinical trial of two × 8 weeks comparing tiotropium (18 μg once daily) + salmeterol (50 μg twice daily) (T + S) to salmeterol + fluticasone (50/500 μg twice daily) (S + F) in COPD (forced expiratory volume in 1 s (FEV(1)) ≤65% predicted, and thoracic gas volume (TGV) ≥120% predicted). Coprimary endpoints were postbronchodilator TGV and exercise endurance time (EET).

In 309 patients, at baseline, prebronchodilator FEV(1) was 1.36 L (46% predicted), TGV was 5.42 L (165% predicted), and EET = 458 s. Relative to S + F, T + S lowered postdose TGV by 182 ± 44 ml after 4 weeks (p < 0.0001) and 87 ± 44 ml after 8 weeks (p < 0.05). EET was nonsignificantly increased following T + S treatment (20 ± 15 s at 4 weeks, 15 ± 13 s at 8 weeks) vs. S + F. BORG dyspnea score at exercise isotime was reduced in favor of T + S.

The two bronchodilators decreased hyperinflation significantly more than one bronchodilator and ICS. This difference was not reflected in EET. (ClinicalTrials.gov number, NCT00530842).