To evaluate the magnitude of reduction in fractional exhaled nitric oxide (FeNO) after an oral corticosteroid (OCS) course in children with mild-to-moderate asthma and assess for any differential response from such treatment on the basis of race.

In the study, the researchers included 92 children (aged 11 ± 3.3 years; White: n = 46 [50%]; Hispanic: n = 30 [33%]; African American [AA]: n = 16 [7%]) who presented to 1 urgent care in Denver, Colorado, for an acute asthma exacerbation from June 2010 to May 2011.

In this prospective cross-sectional cohort study, children aged 7 to 18 years with a physician diagnosis of mild-to-moderate persistent asthma and FeNO measurements within the past 6 months who received a short course of prednisone for acute exacerbation were enrolled. FeNO measurements were obtained at the time of exacerbation and at a 1 week follow-up.

At baseline, AA children had significantly higher mean FeNO values, compared with that of both White (48.9 vs 25.6 parts per billion; P < .5) and Hispanic children (22.5 parts per billion; P < .5), despite similar inhaled corticosteroid doses. During exacerbation, AAs had the highest FeNO values, without a difference in lung function compared with that of non-AAs. After OCSs, there was a 56.6% reduction in FeNO among all children, whereas the relative reduction was similar between that in AAs and non-AAs (53.9% vs 57.8%).

FeNO values were reduced by >50% after a short course of OCSs among all children. AA children showed higher levels of FeNO at baseline and after treatment of exacerbation, although the relative reduction in FeNO was similar among groups.

FeNO is a noninvasive tool for evaluating type 2 airway inflammation and predicting responses to inhaled corticosteroids, but less is known about how FeNO levels change in acute exacerbation or from OCSs. This study reveals clearly that such inflammation is likely alleviated by OCSs across racial and ethnic groups. Given the significantly higher FeNO levels in AA children, however, this also suggests that further research into racial differences in FeNO and how they are clinically correlated is warranted. It may help to explain disparities in health outcomes seen among AA children with asthma or guide therapies. Knowledge of participant environmental factors would be helpful in assessing the significance of the baseline results.