title: Predicting corticosteroid response in chronic obstructive pulmonary disease using exhaled nitric oxide.
abstract: BACKGROUND
  Predicting corticosteroid response in COPD is important but difficult. Response is more likely to occur in association with eosinophilic airway inflammation, for which the fraction of exhaled nitric oxide (Fe(NO)) is a good surrogate marker.
  
  
  OBJECTIVE
  We aimed to establish whether Fe(NO) levels would predict the clinical response to oral corticosteroid in COPD.
  
  
  METHODS
  We performed a double-blind, crossover trial of steroid in patients with COPD. After a 4-week washout of inhaled steroids, patients received prednisone 30 mg/d or matching placebo, in random order, with an intervening 4-week washout. The predictive values of Fe(NO) for clinically significant changes in 6-minute-walk distance (6MWD), spirometry (FEV(1)), and St. George's Respiratory Questionnaire (SGRQ) were calculated.
  
  
  RESULTS
  A total of 65 patients (mean FEV(1) = 57% predicted) were randomized. With prednisone, there was a net increase of 13 m in 6MWD (P = 0.02) and 0.06 L in postbronchodilator FEV(1) (P = 0.02) compared with placebo. The change in SGRQ was not significant. Using receiver operator characteristic analysis, the area under the curve for an increase of 0.2 L in FEV(1) was 0.69 (P = 0.04) with an optimum Fe(NO) cut-point of 50 ppb. The positive and negative predictive values were 67 and 82%, respectively. FE(NO) was not a significant predictor for changes in 6MWD or SGRQ.
  
  
  CONCLUSIONS
  Fe(NO) is a weak predictor of short-term response to oral corticosteroid in COPD, its usefulness being limited to predicting increase in FEV(1). Clinical trial registered with www.anzctr.org.au (ACTRN12605000683639).
authors: Dunedin and Christchurch Schools of Medicine, University of Otago, Dunedin, New Zealand.
authors: Jack F
authors: JF
authors: Dummer
authors: Michael J
authors: MJ
authors: Epton
authors: Jan O
authors: JO
authors: Cowan
authors: Julie M
authors: JM
authors: Cook
authors: Robin
authors: R
authors: Condliffe
authors: C Erik
authors: CE
authors: Landhuis
authors: Andrew D
authors: AD
authors: Smith
authors: D Robin
authors: DR
authors: Taylor
mesh_terms: D000284:Administration, Oral; D000305:Adrenal Cortex Hormones / Q000378:metabolism / Q000627:therapeutic use*; D000368:Aged; D000369:Aged, 80 and over; D000893:Anti-Inflammatory Agents / Q000378:metabolism / Q000627:therapeutic use*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D017079:Exercise Tolerance / Q000187:drug effects; D045853:Exhalation; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008168:Lung / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism*; D011237:Predictive Value of Tests; D011241:Prednisone / Q000378:metabolism / Q000627:therapeutic use*; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000188:drug therapy* / Q000378:metabolism; D011788:Quality of Life; D012129:Respiratory Function Tests; D016896:Treatment Outcome; D016138:Walking
chemical_list: D000305:Adrenal Cortex Hormones; D000893:Anti-Inflammatory Agents; D009569:Nitric Oxide; D011241:Prednisone