D3.138 - Can FeNO predict lung function decline in asthma? A 5-year multicenter cohort study

Fractional exhaled nitric oxide (FeNO) is a non-invasive biomarker of eosinophilic airway inflammation, typically elevated in asthma associated with type 2 inflammation. Although FeNO is useful for asthma phenotyping and treatment monitoring, its long-term predictive value for lung function decline remains uncertain. 

This study aimed to evaluate whether baseline FeNO predicts lung function changes over a five-year period in patients with asthma. 

We analyzed data from the MEGA cohort, a Spanish national multicenter cohort including asthmatic patients with varying disease severity. Patients with complete lung function data at baseline and at 3 and 5 years of follow-up were included. Participants were stratified according to FeNO levels, using a cut-off >35 parts per billion, in accordance with Global Initiative for Asthma (GINA) guidelines. Demographic and clinical variables were collected. Statistical analyses were performed using GraphPad Prism 9. 

A total of 104 patients were included. Baseline demographic and clinical characteristics were similar between groups, except for significantly higher blood and sputum eosinophil counts in patients with elevated FeNO. 

No significant association was found between elevated FeNO levels and lung function decline at either 3 or 5 years of follow-up (all p > 0.05). Adjustment for factors known to influence FeNO levels, including nasal polyposis, blood eosinophilia, and sputum eosinophilia, did not reveal any significant correlations. 

In conclusion, although FeNO is a valuable biomarker for asthma characterization, it does not appear to predict long-term lung function decline. Larger prospective studies with longer follow-up are needed to clarify the prognostic role of FeNO in asthma management