Ontology highlight
ABSTRACT: Rationale
Exhaled nitric oxide (Fe(NO)) is a biomarker of airway inflammation in mild to moderate asthma. However, whether Fe(NO) levels are informative regarding airway inflammation in patients with severe asthma, who are refractory to conventional treatment, is unknown. Here, we hypothesized that classification of severe asthma based on airway inflammation as defined by Fe(NO) levels would identify a more reactive, at-risk asthma phenotype.Methods
Fe(NO) and major features of asthma, including airway inflammation, airflow limitation, hyperinflation, hyperresponsiveness, and atopy, were determined in 446 individuals with various degrees of asthma severity (175 severe, 271 non-severe) and 49 healthy subjects enrolled in the Severe Asthma Research Program.Measurements and main results
Fe(NO) levels were similar among patients with severe and non-severe asthma. The proportion of individuals with high Fe(NO) levels (>35 ppb) was the same (40%) among groups despite greater corticosteroid therapy in severe asthma. All patients with asthma and high Fe(NO) had more airway reactivity (maximal reversal in response to bronchodilator administration and by methacholine challenge), more evidence of allergic airway inflammation (sputum eosinophils), more evidence of atopy (positive skin tests, higher serum IgE and blood eosinophils), and more hyperinflation, but decreased awareness of their symptoms. High Fe(NO) identified those patients with severe asthma characterized by the greatest airflow obstruction and hyperinflation and most frequent use of emergency care.Conclusions
Grouping of asthma by Fe(NO) provides an independent classification of asthma severity, and among patients with severe asthma identifies the most reactive and worrisome asthma phenotype.
SUBMITTER: Dweik RA
PROVIDER: S-EPMC2874447 | biostudies-literature | 2010 May
REPOSITORIES: biostudies-literature
Dweik Raed A RA Sorkness Ronald L RL Wenzel Sally S Hammel Jeffrey J Curran-Everett Douglas D Comhair Suzy A A SA Bleecker Eugene E Busse William W Calhoun William J WJ Castro Mario M Chung Kian Fan KF Israel Elliot E Jarjour Nizar N Moore Wendy W Peters Stephen S Teague Gerald G Gaston Benjamin B Erzurum Serpil C SC
American journal of respiratory and critical care medicine 20100204 10
<h4>Rationale</h4>Exhaled nitric oxide (Fe(NO)) is a biomarker of airway inflammation in mild to moderate asthma. However, whether Fe(NO) levels are informative regarding airway inflammation in patients with severe asthma, who are refractory to conventional treatment, is unknown. Here, we hypothesized that classification of severe asthma based on airway inflammation as defined by Fe(NO) levels would identify a more reactive, at-risk asthma phenotype.<h4>Methods</h4>Fe(NO) and major features of a ...[more]