Rationale: Current asthma guidelines recommend adjusting antiinflammatory 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 with traditional management.

Methods: One hundred eighteen participants with a primary care diagnosis of asthma were randomized 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 every 2 months 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 per patient per year (0.69) in the FENO group and 0.42 (0.79) in the control group (mean difference, –21%; 95% confidence interval [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 (557 vs. 895 µg; mean difference, 338 µg; 95% CI, –640 to –37; p = 0.028).

Conclusions: 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 mo, when compared with current asthma guidelines.

Source: ajrccm.atsjournals.org/cgi/content/short...

Controlled studies have shown that monitoring of the exhaled nitric oxide fraction (FeNO) improves asthma management. However, the studies seldom consider the full range of patients seen in clinical practise. In the present study, the ability of FeNO to reflect asthma control over time is investigated in a regular clinical setting, and meaningful FeNO cut-off points and changes are identified.

Answers to the Asthma Control Questionnaire and FeNO were recorded at least once in 341 unselected asthma patients. The whole population and subgroups were considered, i.e. both inhaled corticosteroid (ICS)-naïve and low or high-to-medium (≤ or >500 µg beclomethasone dipropionate equivalents·day–1) ICS-dose groups.

An FeNO decrease <40% or increase <30% precludes asthma control optimisation or deterioration, respectively (negative predictive value 79 and 82%, respectively). In the present study’s low-dose group, a decrease >40% indicated asthma control optimisation (positive predictive value (PPV) 83%). In ICS-naïve patients, FeNO >35 ppb predicted asthma control improvement in response to ICS (PPV 68%). In most cases, forced expiratory volume in one second assessments were not useful.

In conclusion, in a given patient, exhaled nitric oxide fraction was found to be significantly related to asthma control over time. The overall ability of exhaled nitric oxide fraction to reflect asthma control was reduced in patients using high doses of inhaled corticosteroids. Forced expiratory volume in one second had little additional value in assessing asthma control.


Source: erj.ersjournals.com/cgi/content/abstract...