Abstract
Background: To identify patients who are at risk of accelerated decline in lung function at an early stage of asthma is important. Recent evidence suggests that airway inflammation may be involved in the development of persistent airflow limitation.
Objective: To investigate whether the persistently high level of exhaled nitric oxide fraction (FeNO) is associated with the decline in post-bronchodilator forced expiratory volume in 1 second (FEV1).
Methods: A total of 140 patients with controlled asthma at baseline were enrolled, and were followed with spirometry and FeNO over a 3-year period. We investigated the data of a prospective analysis of the association between the FeNO level and change in FEV1.
Results: Analyses were performed on 122 patients who maintained high (≥40 ppb, n=27) or non-high (n=95) levels of FeNO over time. The baseline FeNO levels showed a weak but significant correlation with the annual rates of decline in FEV1 (r=0.23, p<0.05). FeNO levels of ≥40 ppb were associated with an increased decline in FEV1 compared with FeNO levels of <40 ppb (42.7 vs. 16.7 mL/yr, p<0.0005). Patients with high FeNO had a 48.2% risk of a rapid decline in FEV1 (>40 mL/yr) compared with 18.9% in patients with non-high FeNO (p<0.005). A high level of FeNO was identified as an independent predictor of rapid decline in FEV1 (OR=4.97, p<0.005).
Conclusion: A persistently high level of FeNO among patients with controlled asthma was associated with an accelerated decline in lung function over time.
- © 2014 ERS