Exhaled nitric oxide as a predictor of exacerbation in children with moderate-to-severe asthma: a prospective, 5-month study.
BACKGROUND
Inhaled corticosteroids (ICSs) are recommended as the first line of treatment in children with moderate-to-severe asthma. Exhaled nitric oxide (ENO) has been proposed as a clinically useful marker of control that might help identify patients in whom ICS dose may be safely reduced.


OBJECTIVE
To evaluate the ability of ENO to predict future asthma exacerbations in children with moderate-to-severe asthma undergoing ICS tapering.


METHODS
This is an observational study with no control group. ENO was measured biweekly for 14 weeks in 32 children with moderate-to-severe asthma who were undergoing ICS tapering. Clinical evaluations and spirometry were performed concomitantly, and families kept daily diaries to record symptoms between visits. We used generalized estimating equations to model the In (odds) of an asthma exacerbation in the subsequent 2-week interval as a function of ENO level at the start of the interval while adjusting for age, sex, asthma severity, and current medication use.


RESULTS
We were able to successfully lower ICS doses in 10 (56%) of the 18 children with moderate asthma and in 3 (21%) of the 14 children with severe asthma. In 83 of the 187 follow-up clinical evaluations, children were determined to have had an exacerbation during the preceding 2 weeks. ENO levels, whether expressed as a continuous variable or dichotomized, were not associated with future risk for exacerbations in either unadjusted or adjusted models.


CONCLUSIONS
ENO was not a useful clinical predictor of future asthma exacerbations for children with moderate-to-severe asthma undergoing ICS tapering.
Division of Pulmonary Diseases, Darcy Vargas Hospital, Sao Paulo, Brazil.
Anna Lúcia B
AL
Cabral
William M
WM
Vollmer
Rosa M
RM
Barbirotto
Milton A
MA
Martins
D000280:Administration, Inhalation; D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D001249:Asthma / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology; D015415:Biomarkers / Q000032:analysis*; D002648:Child; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009569:Nitric Oxide / Q000032:analysis*; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies
D000305:Adrenal Cortex Hormones; D015415:Biomarkers; D009569:Nitric Oxide