Sildenafil improves six-minute walk distance in chronic obstructive pulmonary disease: A randomised, double-blind, placebo-controlled trial.

Background. Sildenafil has been found to improve exercise capacity and haemodynamic parameters in patients with various pulmonary disorders. This study was undertaken to evaluate its efficacy in severe chronic obstructive pulmonary disease (COPD). Methods. In this double-blind, randomised, placebo-controlled study, 37 patients with severe COPD received either sildenafil or placebo for 12 weeks. Distance covered in six-minute walk test (6MWD) was taken as primary end-point. Pulmonary artery pressure (PAP) was measured as secondary end point. Results. Thirty-three patients (15 in sildenafil arm and 18 in placebo arm) completed the study. Non-parametric tests were used for comparison. There was significant increase in 6MWD from baseline after three months of follow-up in sildenafil users (median change in distance covered in six-minute walk test (Δ6MWD)=190m) as compared to placebo users (Δ6MWD=0m, p< 0.05). The PAP decreased significantly (χ2=14.94, p<0.05) in sildenafil group after three months, while it did not change significantly among placebo group (χ 2=3.84, p>0.05). Conclusion. Sildenafil improved 6MWD and PAP in patients with severe COPD. This trial has been registered with Indian Council of Medical Research (ICMR) Trial Registry. [CTRI Registry Number: CTRI/ 2009/091/000017]