Abstract
Question. To evaluate whether exhaled NO (FENO0.05) is associated with pathophysiological characteristics such as airway tone (bronchodilator response) and inflammation (inhaled corticosteroid [ICS]-dependent inflammation), and with phenotypes of childhood asthma.
Methods: We performed multivariate and k-means cluster analyses in a population of 169 asthmatic children (age ± SD: 10.5±2.6 years) recruited in a cohort characterized in a cross-sectional design using 28 parameters of different domains: atopy, environment (tobacco), control, exacerbations, treatment (ICS and long-acting bronchodilator agonist), and lung function (airway architecture and tone).
Results: Two subject-related (height and atopy) and two disease-related characteristics (bronchodilator response and ICS dose>200 μg/d) explained 36% of exhaled NO variance. Principal component analysis isolated 9 domains and 4 clusters were identified: 1 (47%): boys, unexposed to tobacco, with well-controlled asthma; 2 (26%): girls, unexposed to tobacco, with well-controlled asthma; 3 (6%): girls or boys, unexposed to tobacco, with uncontrolled asthma and increased tone, and 4 (21%): girls or boys, exposed to parental smoking, with small airway to lung size ratio and uncontrolled asthma. Importantly, FENO0.05 was not different in these four clusters.
Conclusion: Despite its relationships with pathophysiological characteristics, FENO0.05 does not help to identify a relevant phenotype of asthmatic children.
- © 2011 ERS