Management of Asthma Based on Exhaled Nitric Oxide in Addition to Guideline-Based Treatment for Inner-City Adolescents and Young Adults: A Randomised Controlled Trial
Niya H. Wanich, MD, Michael S. Kaplan, MD
Los Angeles, CA
Szefler SJ, Mitchell H, Sorkness CA, et al. Lancet. 2008;372(9643):1065–1072
PURPOSE OF THE STUDY. To determine whether the use of exhaled nitric oxide (NO) measurements to modify asthma treatment regimens improves asthma control when used as an adjunct to management based on national asthma care guidelines.
STUDY POPULATION. A randomized, double-blind, parallel-group trial at 10 centers in the United States monitored a total of 546 inner-city subjects, 12 to 20 years of age, with poorly controlled asthma.
METHODS. Physician assessment was performed every 6 to 8 weeks for 46 weeks, during which patients were evaluated for asthma symptoms, pulmonary function, and exhaled NO, a marker of airway inflammation. At each visit, treatment was stepped up or down on the basis of the National Asthma Education and Prevention Program (NAEPP) asthma care guidelines for the control group or the NAEPP guidelines plus measurements of fraction of exhaled NO (FeNO) for the NO group.
RESULTS. There was no difference between the control group and the NO group with respect to asthma symptoms, pulmonary function, or asthma exacerbations. By the end of the study, patients in the NO group were receiving higher doses of inhaled corticosteroids (difference in fluticasone doses: 119 µg; P = .001) than were those in the control group, with a greater number receiving long-acting ?2-adrenergic receptor agonists. Adverse events did not differ between the treatment groups.
CONCLUSIONS. The addition of FeNO as an indicator of asthma control resulted in higher doses of inhaled corticosteroids, without clinically important improvements in symptomatic asthma control.
REVIEWERS COMMENTS. Because asthma symptoms and exacerbations are linked to underlying airway inflammation, it seems that using measurements of biomarkers that are indicators of airway inflammation (FeNO) to direct asthma management would improve asthma control. However, this study showed that use of current NAEPP guidelines for asthma treatment alone provided good asthma control for inner-city adolescents and young adults. The addition of FeNO measurements resulted in higher doses of inhaled corticosteroids and long-acting ?2-adrenergic receptor agonists, without producing additional improvements in asthma symptoms, lung function, or need for health care.