The change of FeNO is correlated with asthma control and lung function

Objective: To investigate the changes in fractional exhaled nitric oxide (FeNO) after treatment and the association between FeNO changes and the prognosis and lung function of children with asthma.

Methods: A total of 144 children newly enrolled with non-standardized treatment of asthma were recruited between September 2020 and December 2021. The children were divided into two groups according to the initial FeNO (0 day), and the changes in FeNO after Budesonide/Formoterol Inhalation Powder Mist (B/FIPM) treatment were observed in different subgroups in correlation with future outcomes after 1 year (well controlled or partly controlled) and lung function.

Results: The study showed that B/FIPM therapy significantly reduced FeNO levels and eosinophils (EOS) counts, improving pulmonary function (P < 0.01). FeNO levels significantly decreased in the well controlled group after 1 week treatment but not after 2 weeks. The partly controlled group showed sustained benefits after 2 weeks treatment (P < 0.01). Besides, among the patients with initial FeNO ≤35 ppb, the proportion of well controlled outcome was significantly higher in the group of ΔFeNO >0 (72.73 %) than that in the ΔFeNO ≤0 group (53.85 %) (P = 0.042).

Conclusion: B/FIPM is effective in reducing FeNO levels and EOS counts and restoring lung function in children with asthma. In addition, post-treatment changes in FeNO were predictive of prognosis and correlated with post-treatment lung function.