The Use of Exhaled Nitric Oxide to Guide Asthma Management: A Randomised Controlled Trial. [Am J Respir Crit Care Med] Journal article

RATIONALE: Current asthma guidelines recommend adjusting anti-inflammatory treatment on the basis of the results of lung function tests and symptom assessment, neither of which are closely associated with airway inflammation.
OBJECTIVES: We tested the hypothesis that titrating corticosteroid dose using the concentration of exhaled nitric oxide in exhaled breath (FENO) results in fewer asthma exacerbations and more efficient use of corticosteroids, when compared to traditional management.
METHODS: 118 participants with a primary care diagnosis of asthma were randomised to a single blind trial of corticosteroid therapy based on either FENO measurements (n = 58) or British Thoracic Society guidelines (n = 60). Participants were assessed monthly for 4 months and then two monthly for a further 8 months. The primary outcome was the number of severe asthma exacerbations. Analyses were by intention to treat.
MEASUREMENTS AND MAIN RESULTS: The estimated mean (SD) exacerbation frequency was 0.33/patient/year (0.69) in the FENO group and 0.42 (0.79) in the control group (mean difference -21% [95% CI -57% to 43%] p=0.43). Overall the FENO group used 11% more inhaled corticosteroid ([95% CI -17% to 42%] p=0.40), although the final daily dose of inhaled corticosteroid was lower in the FENO group (557microg vs. 895microg, mean difference 338microg [95% CI -640 to -37] p=0.028).
CONCLUSION: An asthma treatment strategy based on the measurement of exhaled nitric oxide did not result in a large reduction in asthma exacerbations or in the total amount of inhaled corticosteroid therapy used over 12 months, when compared with current asthma guidelines. www.controlled-trials.com i.d. = ISRCTN08067387.

Am J Respir Crit Care Med