Fractional exhaled nitric oxide (FeNO) may predict exercise-induced bronchoconstriction (EIB) in schoolchildren with atopic asthma

BackgroundThere is a need for the performance of exercise-induced bronchoconstriction (EIB) tests in the monitoring of childhood asthma control. We aimed to evaluate whether in children with atopic asthma, EIB can be predicted by one or more of the following parameters or by their combination: fractional exhaled nitric-oxide (FeNO), allergy profile, asthma treatment, total IgE serum concentration and eosinophil blood count (EBC).MethodsIt was a retrospective, cross-sectional study. We evaluated data from medical documentation of children with atopic asthma who had performed standardized spirometric exercise challenge test.ResultsOne hundred and twenty six patients with atopic asthma, aged 5–18, were included in the analysis. There were two groups of patients: the EIB group (n = 54) and the no-EIB group (n = 72). The median FeNO level prior to exercise in the EIB group was 27.6 vs. 16.3 ppb in the no-EIB group (p = 0.002). FeNO level higher than 16 ppb had the highest diagnostic value to confirm EIB. When using the FeNO level of >16 ppb, the sensitivity, specificity, negative predictive and positive predictive values for EIB were 83%, 46.9%, 74.2%, and 60%, respectively. In the EIB group, the degree of FeNO elevation did correlate positively with the absolute fall in FEV1 (p = 0.002; r = 0.45). The FeNO value of >16 ppb, EBC value of >350 cell/mm3 and allergy to house dust mites presented the highest odds ratios of EIB. However, the FeNO value of >16 ppb was the only independent odds ratio of EIB.ConclusionsElevated FeNO level increased the odds of EIB in asthmatic schoolchildren, independently of other asthma severity markers and the intensity of anti-asthma therapy. It seems likely that FeNO measurement may act as a screening tool and help to prevent under-diagnosis and under-treatment of exercise-induced bronchoconstriction in schoolchildren with atopic asthma.

► We aimed to evaluate if in children with atopic asthma, EIB can be predicted by certain parameters.
► We evaluated data from medical documentation of atopic asthmatic schoolchildren.
► Elevated FeNO level increased the odds of EIB in asthmatic schoolchildren, independently.
► It seems likely that FeNO may act as a screening tool for EIB in atopic asthmatic schoolchildren.