Exhaled nitric oxide and clinical phenotypes of childhood asthma

• Published in: Respiratory research 2011-05, Vol.12 (74), p.65-65, Article 65
• Main Authors: Mahut, Bruno, Peyrard, Séverine, Delclaux, Christophe
• Format: Article
• Language: English
• Subjects: Administration, Inhalation; Adolescent; Adrenal Cortex Hormones - administration & dosage; Adrenergic beta-Agonists - administration & dosage; Asthma - diagnosis; Asthma - drug therapy; Asthma - metabolism; Asthma - physiopathology; Asthma in children; Biomarkers - metabolism; Breath Tests; Bronchial Provocation Tests; Bronchodilator Agents - administration & dosage; Child; Cluster Analysis; Corticosteroids; Cross-Sectional Studies; Exhalation; Female; Forced Expiratory Flow Rates; Forced Expiratory Volume; Genetic aspects; Health aspects; Humans; Linear Models; Lung - drug effects; Lung - metabolism; Lung - physiopathology; Male; Nitric oxide; Nitric Oxide - metabolism; Parenting; Paris; Phenotype; Physiological aspects; Plethysmography; Predictive Value of Tests; Principal Component Analysis; Residual Volume; Respiratory agents; Risk Assessment; Risk Factors; Spirometry; Total Lung Capacity; Vital Capacity
• ISSN: 1465-993X; 1465-9921; 1465-993X
• DOI: 10.1186/1465-9921-12-65

Whether exhaled NO helps to identify a specific phenotype of asthmatic patients remains debated. Our aims were to evaluate whether exhaled NO (FENO(0.05)) is independently associated (1) with underlying pathophysiological characteristics of asthma such as airway tone (bronchodilator response) and airway inflammation (inhaled corticosteroid [ICS]-dependant inflammation), and (2) with clinical phenotypes of asthma.We performed multivariate (exhaled NO as dependent variable) and k-means cluster analyses in a population of 169 asthmatic children (age ± SD: 10.5 ± 2.6 years) recruited in a monocenter cohort that was characterized in a cross-sectional design using 28 parameters describing potentially different asthma domains: atopy, environment (tobacco), control, exacerbations, treatment (inhaled corticosteroid and long-acting bronchodilator agonist), and lung function (airway architecture and tone). Two subject-related characteristics (height and atopy) and two disease-related characteristics (bronchodilator response and ICS dose > 200 μg/d) explained 36% of exhaled NO variance. Nine domains were isolated using principal component analysis. Four clusters were further identified: cluster 1 (47%): boys, unexposed to tobacco, with well-controlled asthma; cluster 2 (26%): girls, unexposed to tobacco, with well-controlled asthma; cluster 3 (6%): girls or boys, unexposed to tobacco, with uncontrolled asthma associated with increased airway tone, and cluster 4 (21%): girls or boys, exposed to parental smoking, with small airway to lung size ratio and uncontrolled asthma. FENO(0.05) was not different in these four clusters.In conclusion, FENO(0.05) is independently linked to two pathophysiological characteristics of asthma (ICS-dependant inflammation and bronchomotor tone) but does not help to identify a clinically relevant phenotype of asthmatic children.