Computed tomography assessment of airway dimensions with combined tiotropium and indacaterol therapy in COPD patients

Background and objectiveCombining a long-acting muscarinic antagonist with a long-acting (2)-agonist has been shown to be pharmacologically useful in patients with chronic obstructive pulmonary disease (COPD). The aim of the present study was to evaluate the effectiveness of the dual bronchodilator therapy on airway dimensions in COPD. MethodsPatients (n=54) were randomly assigned to receive tiotropium (18g once daily), indacaterol (150g once daily) or tiotropium plus indacaterol for 16 weeks. Quantitative computed tomography (CT), pulmonary function and health status (St. George's Respiratory Questionnaire) were measured. ResultsCompared with tiotropium or indacaterol alone, combination therapy resulted in a significant decrease in percentage wall area (WA%) and wall thickness, corrected for body surface area, and an increase in luminal area (Ai/BSA). Concurrent treatment was superior to monotherapy in physiological indices, including forced vital capacity, forced expiratory volume in 1s (FEV1) and inspiratory capacity. The changes in WA% and Ai/BSA were significantly correlated with changes in FEV1 (r=-0.44, P<0.01 and r=0.37, P<0.01). There were more significant improvements in SGRQ scores after treatment with combined therapy than with either treatment alone. ConclusionsConcurrent therapy with tiotropium and indacaterol is effective for COPD patients to promote reduction in airway wall thickness, bronchodilation, and improvements in lung function compared with a single inhaler. Current available long-acting bronchodilators are the once-daily anticholinergic tiotropium and (2)-agonist indacaterol. Concurrent use of two bronchodilators with different modes of action may provide patients and physicians with more benefit in treating COPD.