High Exhaled Nitric Oxide Levels May Predict Bronchial Reversibility in Allergic Children with Asthma or Rhinitis

Abstract

Background. Allergic asthma and rhinitis may be associated. Airway inflammation is shared by both disorders. The measure of the fractional concentration of exhaled nitric oxide (FeNO) may be considered as a surrogate marker for airway inflammation, mainly in allergic patients. Reversibility to bronchodilation (BD) testing is a functional characteristic of asthma. Objective. The aim of this study was to evaluate whether FeNO may predict reversibility to BD in a pediatric cohort of allergic subjects with asthma (180) or rhinitis (150). Methods. Lung function (including forced expiratory volume at the first second (FEV1), forced volume capacity (FVC), forced expiratory flow at 25–75% of volume capacity (FEF 25–75)), FeNO measurement, and BD testing were performed in all children. Results. Lung function, FeNO, and sensitization type were significantly different in the two groups. A strong correlation was found between FeNO and ΔFEV1 after BD. Two main predictors of reversibility were FeNO values >34 ppb [Odds RatioAdj (ORAdj) = 1.9] and sensitization to perennial allergens (ORAdj = 1.7). Conclusions. This study provided evidence that FeNO was strongly related with the response to BD testing and could predict bronchial reversibility in children with allergic rhinitis or asthma. Therefore, a simple FeNO measurement could suggest relevant information about bronchial reversibility.