Effect of fluticasone propionate/

salmeterol plus tiotropium versus tiotropium on walking endurance in COPD To the Editor: Exercise intolerance is a hallmark feature of chronic obstructive pulmonary disease (COPD) and is associated with premature mortality [1]. Tiotropium (TIO) is effective in improving cycling exercise tolerance [2, 3] and walking endurance time in COPD [4]; these properties are thought to be associated with reductions in operating lung volume and the perception of dyspnoea during exercise [2, 3, 5]. What is less certain, however, is the extent to which these benefits of TIO on exercise duration can be further improved with the use of additional inhalational therapy. We examined whether the addition of fluticasone propionate/salmeterol combination (FSC) to TIO improved endurance time during the endurance shuttle walking test (ESWT) more than TIO alone in patients with COPD. Our specific objectives were to compare endurance time during the ESWT and evaluate the impact on lung function of TIO alone or in combination with FSC. We hypothesised that the addition of FSC to TIO would improve endurance time during the ESWT compared to TIO alone. This was an 8-week, multicentre, placebo-controlled, double-blind, randomised, parallel group study. Patient