Exhaled Nitric Oxide Predicts Glucocorticoid Response in Acute Exacerbations of Chronic Obstructive Pulmonary Disease

This retrospective study evaluated the clinical value of fractional exhaled nitric oxide in predicting glucocorticoid response in patients with acute exacerbations of chronic obstructive pulmonary disease. Based on the critical value of fractional exhaled nitric oxide (FeNO) levels ≥25 ppb at admission, patients were categorized into two groups: the high FeNO group (n = 61) and the low FeNO group (n = 61). All patients received standard basic treatment, which included inhaled corticosteroids (ICS), short-acting β2 receptor agonists (SABA), and short-acting anticholinergic drugs (SAMA). The treatment subgroup was administered additional systemic glucocorticoid therapy. The primary outcomes of this study were improvements in forced expiratory volume in 1 s (FEV1% pred) and the COPD Assessment Test (CAT) score. Secondary outcomes included changes in the duration of hospital stay and levels of exhaled nitric oxide. Baseline exhaled nitric oxide (FeNO) levels were positively correlated with blood eosinophil counts. In the high-level FeNO group, patients in the treatment group showed significant improvements in lung function, a reduction in the COPD Assessment Test (CAT) score, and lower exhaled nitric oxide levels compared with the control group. Conversely, in the low-level FeNO group, no significant differences were observed between the treatment and control subgroups. These findings indicate that baseline fractional exhaled nitric oxide can identify eosinophilic airway inflammation and predict responsiveness to glucocorticoid therapy, supporting personalized glucocorticoid treatment selection in acute exacerbations of chronic obstructive pulmonary disease. This retrospective study shows that baseline fractional exhaled nitric oxide identifies eosinophilic airway inflammation and predicts glucocorticoid response in acute exacerbations of chronic obstructive pulmonary disease, supporting personalized treatment and reducing hospital stay.