title: Sildenafil improves six-minute walk distance in chronic obstructive pulmonary disease: a randomised, double-blind, placebo-controlled trial.
abstract: 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 (delta6MWD) = 190m) as compared to placebo users (delta6MWD = 0m, p < 0.05). The PAP decreased significantly (chi2 = 14.94, p < 0.05) in sildenafil group after three months, while it did not change significantly among placebo group (chi2 = 3.84, p > 0.05).
  
  
  CONCLUSIONS
  Sildenafil improved 6MWD and PAP in patients with severe COPD.
authors.affiliation: Allergy and Pulmonary Division, SMS Medical College and Hospital, Jaipur (Rajasthan), India.
authors.forename: Ravinder Singh
authors.initials: RS
authors.lastname: Rao
authors.forename: Sheetu
authors.initials: S
authors.lastname: Singh
authors.forename: Bharat Bhushan
authors.initials: BB
authors.lastname: Sharma
authors.forename: V V
authors.initials: VV
authors.lastname: Agarwal
authors.forename: Virendra
authors.initials: V
authors.lastname: Singh
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D001794:Blood Pressure / Q000502:physiology; D004311:Double-Blind Method; D017079:Exercise Tolerance / Q000502:physiology; D005541:Forced Expiratory Volume; D006801:Humans; D008875:Middle Aged; D058986:Phosphodiesterase 5 Inhibitors / Q000627:therapeutic use*; D010879:Piperazines / Q000009:adverse effects / Q000627:therapeutic use*; D011651:Pulmonary Artery / Q000502:physiology; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy* / Q000503:physiopathology; D011687:Purines / Q000009:adverse effects / Q000627:therapeutic use; D000068677:Sildenafil Citrate; D018709:Statistics, Nonparametric; D013450:Sulfones / Q000009:adverse effects / Q000627:therapeutic use*; D016138:Walking
chemical_list: D058986:Phosphodiesterase 5 Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D000068677:Sildenafil Citrate