Is fractional exhaled nitric oxide (FeNO) associated with asthma control in children?

The most important way to achieve and maintain asthma control is to reduce airway inflammation. Fractional exhaled nitric oxide (FeNO) levels have been used as a marker of airway inflammation.

To evaluate the association between FeNO levels and the asthma control status in children.

This was a cross-sectional clinical trial in children with atopic asthma aged ≥ 7 years. The levels of asthma control were assessed by using the criteria from the GINA Guideline. FeNO levels and spirometry were measured. Asthma medications were recorded. The association between FeNO levels and asthma control status and the usage of asthma medications were analyzed.

One hundred and fourteen asthmatic children aged 12.1 ± 3.5 years were recruited into the study. Most of the patients had mild persistent asthma (79.8%). The administration of inhaled corticosteroid (ICS) was reported in 82.4% of cases. According to the GINA Guideline, 34.2% of cases were controlled, 44.7% were partly controlled and 21.1% were uncontrolled. We found that there was no significant difference in the median FeNO levels in the controlled, partly controlled and uncontrolled groups [19.2 (95% CI 5.1-108.9), 24.9 (2.2-85.7), and 39.2 (2.4-192.3) ppb, respectively (p = 0.24)]. However, in 20 cases who did not receive ICS treatment, the median FeNO levels showed a significant difference among controlled, partly controlled and uncontrolled groups [31.8 (95% CI 11.1-108.9), 34.1 (5.3-81.8), 92.0 (46.3-192.3) ppb, respectively; p <0.05].

FeNO levels were increased in ICS-treated asthmatic patients with less asthma control, albeit with no statistically significance. However, FeNO levels correlated with poor asthma control status in ICS untreated cases.