Purpose of the Study. To determine if measurement of exhaled nitric oxide (FeNO) adds to guideline-driven asthma management for patients with chronic asthma.
Study Population. A total of 110 patients (aged 12–75 years) with chronic asthma on inhaled corticosteroids (ICSs) for at least 6 months using stable doses for 6 weeks were initially evaluated. Exclusion criteria included ≥4 courses of oral prednisone in the previous 12 months, admission to the hospital because of asthma in the previous 6 months, ICU admission at any time in the past, or >10 pack-years (an average of 1 pack of cigarettes smoked per day for >10 years) of cigarette smoking.
Methods. This was a single-blind, placebo-controlled study. In phase 1 the ICS dose was adjusted on the basis of FeNO or guidelines-based algorithms. When the optimal dose was determined, patients were managed for 12 months.
Results. There were 46 patients in the FeNO group and 48 patients in the guideline group who completed the study. The final ICS dose for fluticasone was 370 μg/day (95% confidence interval [CI]: 263–477 μg) in the FeNO group and 641 μg/day (95% CI: 526–756 μg; P = .003) in the guideline group. The rate of exacerbations per patient per year was 0.49 (95% CI: 0.31–1.49) in the FeNO group, compared with 0.9 (95% CI: 0.31–1.49; P = .27) in the guideline group. There was no difference in the number, frequency, or time of first exacerbation between groups. There was no significant difference in nighttime awakenings, bronchodilator use, percent symptom-free days, or number of oral corticosteroid courses. There also was no difference in percent sputum eosinophils or pulmonary-function tests.
Conclusions. With the use of FeNO, control of asthma can be obtained with a lower ICS dose.
Reviewer Comments. The values for FeNO differ from other studies because a flow rate of 250 mL/second was used instead of 50 mL/second. The control group had downward titration of dose on the basis of symptoms, which was achieved only in a minority of patients. This may have magnified the observed difference in the ICS dose. This and subsequent studies suggest that markers of airway inflammation are becoming accepted as important surrogate markers of asthma control.
- Copyright © 2006 by the American Academy of Pediatrics