Effects of adding salmeterol/fluticasone propionate to tiotropium on airway dimensions in patients with chronic obstructive pulmonary disease

Background and objective: Although salmeterol/fluticasone propionate combination (SFC) therapy has been widely used for the treatment of COPD, the relationship between airway dimensions and improvement in pulmonary function remains unknown. The aim of this study was to compare the effects of SFC in combination with tiotropium (Tio) and Tio alone, on airway dimensions and pulmonary function in COPD patients. Methods: Thirty COPD patients were randomized to receive inhaled Tio (18 mu g once daily) or inhaled SFC (50/250 mu g twice daily) plus Tio for 12 weeks. Spirometry and CT were performed, and the St. George's Respiratory Questionnaire (SGRQ) was completed, before and after the trial. Airway dimensions were assessed by a validated CT technique, and airway wall area (WA) corrected for body surface area (BSA), percentage wall area (WA%), absolute wall thickness (T)/root BSA, and luminal area (Ai)/BSA at the right apical segmental bronchus, were measured. Results: Treatment with SFC plus Tio significantly decreased WA/BSA (P < 0.05), WA% (P < 0.01) and T/root BSA (P < 0.01), and increased Ai/BSA (P < 0.01), whereas treatment with Tio alone had no effect. The changes in WA/BSA and Ai/BSA were significantly correlated with increases in FEV1 (r = 0.48, P < 0.05, and r = 0.36, P < 0.05, respectively). There were significant improvements in SGRQ scores after treatment with SFC plus Tio. Conclusions: Airway wall thickening and airway narrowing decreased after treatment with SFC plus Tio, and the changes in airway dimensions were proportional to the improvements in FEV1. These results suggest that SFC plus Tio is more effective than Tio alone in the management of COPD patients.