title: Response of exhaled nitric oxide to inhaled corticosteroids in patients with stable COPD: A systematic review and meta-analysis.
abstract: BACKGROUND
  To our knowledge, no meta-analysis has investigated the response of FeNO levels to corticosteroid treatment in ex-smokers with chronic obstructive pulmonary disease (COPD).
  
  
  OBJECTIVE
  This meta-analysis assessed the potential role of fraction of exhaled nitric oxide (FeNO) as a biomarker for corticosteroid response in ex-smokers with stable COPD.
  
  
  METHODS
  Medline, Cochrane, EMBASE, Google Scholar databases were searched until November 5, 2014 using the following terms: corticosteroid, chronic obstructive pulmonary disease, COPD, nitric oxide, NO, exhaled nitric oxide. Only randomized controlled trials (RCT) or two-arm prospective studies were included. The primary outcome measure was FeNO before and after treatment with inhaled corticosteroids (ICS) in ex-smokers with COPD. Sensitivity analysis was also performed.
  
  
  RESULTS
  Five studies were included in the analysis with a total of 171 COPD patients. All five studies included 125 ex-smokers and two of these also included 46 current smokers. There was a significant decrease of FeNO in ex-smoking COPD patients following inhaled corticosteroid treatment (-7.51, 95% CI: -11.51 to -3.51; P =0.003); and in a population of subjects that included both smokers and ex-smokers (-1.99, 95% CI: -3.41 to -0.56; P =0.006).
  
  
  CONCLUSIONS
  Our findings indicate that FeNO levels significantly decreased with corticosteroid treatment in ex-smokers with COPD. Additional studies are required to evaluate whether concurrent smoking has significant effect on FeNO response to ICS.
authors.affiliation: Respiratory Unit, Department of Medicine, Tropicana Medical Centre, Petaling Jaya, Selangor, 47810, Malaysia.
authors.forename: Chor-Shen
authors.initials: CS
authors.lastname: Lim
authors.affiliation: Respiratory Unit, Department of Medicine, Tropicana Medical Centre, Petaling Jaya, Selangor, 47810, Malaysia.|Respiratory Unit, Faculty of Medicine, Universiti Teknologi MARA, Selayang, Selangor, 68100, Malaysia.
authors.forename: Fauzi Abdul
authors.initials: FA
authors.lastname: Rani
authors.affiliation: Respiratory Unit, Department of Medicine, Tropicana Medical Centre, Petaling Jaya, Selangor, 47810, Malaysia.
authors.forename: Lan-Eng
authors.initials: LE
authors.lastname: Tan
mesh_terms: D000280:Administration, Inhalation; D000305:Adrenal Cortex Hormones / Q000008:administration & dosage*; D001944:Breath Tests; D045853:Exhalation; D005541:Forced Expiratory Volume / Q000187:drug effects*; D006801:Humans; D009569:Nitric Oxide / Q000032:analysis*; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology
chemical_list: D000305:Adrenal Cortex Hormones; D009569:Nitric Oxide
keywords: COPD; NO; inhaled corticosteroid; smoker