title: Heterogeneity of FeNO response to inhaled steroid in asthmatic children.
abstract: BACKGROUND
  Nitric oxide in exhaled air is regarded as an inflammation marker, and may be used to monitor the anti-inflammatory control from inhaled corticosteroids (ICSs). However, this response to ICSs exhibits a heterogeneous pattern.
  
  
  OBJECTIVE
  The study aimed to describe the independent variables associated with the heterogeneity in the response of exhaled nitric oxide to ICSs.
  
  
  METHODS
  Exhaled nitric oxide (FeNO), lung function, bronchial hyper-responsiveness (BHR), specific IgE to common inhalant allergens, blood eosinophils, other atopic manifestations and variants in nitric oxide synthethase 1 (NOS1) gene were studied in a double-blind, placebo-controlled crossover comparison of budesonide (BUD) Turbohaler 1600 mcg daily vs. placebo in asthmatic schoolchildren.
  
  
  RESULTS
  Forty children were included in the study from a screening of 184 asthmatic children with moderately persistent asthma, well controlled on regular BUD 400 mcg daily: 20 children with normal FeNO and 20 with raised FeNO. FeNO, BHR and forced expiratory volume in 1 s improved significantly after BUD 1600 mcg (BUD1600). However, FeNO after ICS treatment exhibited a Gaussian distribution and FeNO was significantly raised in 15 children. Allergy and BHR, but none of the other independent variables under study were significantly related to FeNO after BUD1600.
  
  
  CONCLUSIONS
  Exhaled nitric oxide exhibited a heterogeneous response to ICS in asthmatic schoolchildren. Allergy and BHR were driving FeNO level independently of high-dose steroid treatment. This should be considered when using FeNO for steroid dose titration and monitoring of ICS anti-inflammatory control in asthmatic children.
authors.affiliation: Department of Paediatrics, Rigshospitalet, National University Hospital, Copenhagen, Denmark.
authors.forename: F
authors.initials: F
authors.lastname: Buchvald
authors.forename: H
authors.initials: H
authors.lastname: Eiberg
authors.forename: H
authors.initials: H
authors.lastname: Bisgaard
mesh_terms: D000280:Administration, Inhalation; D000293:Adolescent; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D001249:Asthma / Q000188:drug therapy* / Q000378:metabolism*; D015415:Biomarkers / Q000032:analysis; D001944:Breath Tests; D019819:Budesonide / Q000008:administration & dosage* / Q000627:therapeutic use; D016022:Case-Control Studies; D002648:Child; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008168:Lung / Q000378:metabolism; D008297:Male; D009330:Nebulizers and Vaporizers; D009569:Nitric Oxide / Q000032:analysis*; D012044:Regression Analysis
chemical_list: D000893:Anti-Inflammatory Agents; D015415:Biomarkers; D009569:Nitric Oxide; D019819:Budesonide