Exhaled nitric oxide predicts asthma relapse in children with clinical asthma remission

Abstract

Background: Nitric oxide in exhaled air (FE NO ) is a marker of eosinophilic airway inflammation. A study was undertaken to determine whether FE NO predicts asthma relapse in asymptomatic asthmatic children in whom inhaled corticosteroids are discontinued. Methods: Forty children (21 boys) of mean age 12.2 years on a median dose of 400 mg budesonide or equivalent (range 100-400) were included. FE NO was measured before and 2, 4, 12, and 24 weeks after withdrawal of steroids. A relapse was defined as more than one exacerbation per month, or need for b agonist treatment on 4 days per week for at least 2 weeks, or diurnal peak flow variability of .20%. FE NO measurements were performed online with an expiratory flow of 50 ml/s. Results: Nine patients relapsed. Two and 4 weeks after withdrawal of steroids geometric mean FE NO in children who were about to relapse was higher than in those who did not relapse: 35.3 ppb v 15.7 ppb at 2 weeks (ratio 2.3; 95% CI 1.2 to 4.1; p = 0.01) and 40.8 ppb v 15.9 ppb at 4 weeks (ratio 2.6; 95% CI 1.3 to 5.1). An FE NO value of 49 ppb at 4 weeks after discontinuation of steroids had the best combination of sensitivity (71%) and specificity (93%) for asthma relapse. Conclusion: FE NO 2 and 4 weeks after discontinuation of steroids in asymptomatic asthmatic children may be an objective predictor of asthma relapse.

Exhaled NO: Determinants and Clinical Application in Children With Allergic Airway Disease

“…When FeNO was <22 ppb, it was useful for predicting successful steroid reduction. 48 Another study in children presented 22.9 ppb as a FeNO cutoff with a sensitivity of 80% and a specificity of 60% for predicting exacerbation. 50 Emerging information indicates that assessment of within-individual changes in FeNO may be a more accurate method for In general for children, elevated eosinophil counts in sputum may be more sensitive for predicting asthma exacerbations or loss of asthma control after steroid reduction than elevated FeNO.…”

Functional Lung Examination in Diagnostics of Asthma and Its Phenotypes

“…High levels of FeNO predict steroid responsiveness. Moreover, it can predict the relapse of asthma symptoms after steroid treatment withdrawal [13].…”

Intérêt de la mesure de l’inflammation en clinique dans l’asthme

“…En ce qui concerne les seuils permettant de prédire une perte de contrôle de l'asthme, Zacharasiewicz a rapporté qu'un taux de FE NO supérieur à 22 ppb chez des enfants traités par stéroïdes inhalés est associé à un risque six fois supérieur de perte de contrôle de l'asthme pendant la réduction du traitement par corticosté-roïdes [82] . Une autre étude, toujours chez l'enfant, a trouvé qu'un taux de FE NO supérieur à 49 ppb un mois après l'arrêt du traitement par corticostéroïdes inhalés présentait une sensibilité et une spécificité optimale pour la prédiction d'une perte de contrôle [96] . Le taux de FE NO n'est pas corrélé au VEMS [97] .…”