Purpose of the Study. To examine the clinical utility of noninvasive measures of airway inflammation as predictors for successful inhaled corticosteroid (ICS) dose reduction in children with asthma.
Study Population. Forty children (aged 6–17 years) with stable asthma on a constant ICS dose and eligible for steroid dose reduction.
Methods. Children were followed prospectively every 8 weeks with noninvasive measures of airway inflammation including exhaled nitric oxide (eNO), sputum induction with bronchial hyperreactivity testing, and exhaled breath condensate. Physicians who were unaware of the results of inflammatory measures made reductions in the steroid dose on the basis of clinical assessment and spirometry. Multiple logistic-regression models were used to determine the usefulness of noninvasive inflammatory markers in predicting successful steroid reduction.
Results. Seventy-five percent of patients tolerated a reduction in steroid dose for at least 2 months; however, 15 (38%) of the 40 patients’ conditions subsequently failed ICS dose reduction and experienced an asthma exacerbation. All children with absence of sputum eosinophils successfully tolerated dose reduction. Increased eNO ≥22 ppb (odds ratio: 6.3; 95% confidence interval: 3.75–10.58) and increased sputum eosinophils ≥3% (odds ratio: 1.38; 95% confidence interval: 1.06–1.81) were significant predictors of failed ICS dose reduction.
Conclusions. Noninvasive measures of airway inflammation may be useful tools in optimizing treatment of children with asthma.
Reviewer Comments. These findings suggest that noninvasive measures of airway inflammation are potential adjunctive tools that can be used in pediatric patients who appear clinically stable. However, their clinical usefulness may be limited by several factors. Sputum induction was not successfully performed in 25% of the children, and some measures including bronchial hyperreactivity and breath condensate did not prove to be useful predictors in this study. In addition, criteria for predicting failure were met in 6 (21%) of 28 and 19 (39%) of 49 occasions for sputum eosinophil and eNO cutoffs, respectively, when the child was successfully weaned on the basis of clinical judgment. Conversely, use of noninvasive markers would have prevented an attempt to wean steroids on >70% of occasions when patients subsequently experienced an exacerbation. Inflammatory markers as sole predictors of success or failure will likely result in both significant undertreatment and overtreatment with ICSs. Treatment algorithms that include noninvasive airway inflammatory markers in conjunction with clinical markers are likely the best approach to optimize therapy in children who appear clinically stable.
- Copyright © 2006 by the American Academy of Pediatrics