Predictive value of exhaled nitric oxide in assessing the therapeutic efficacy of corticosteroid treatment for acute exacerbation of chronic obstructive pulmonary disease.

Fractional exhaled nitric oxide (FeNO) is a promising biomarker of airway inflammation. Its predictive value for corticosteroid responsiveness during acute exacerbations of chronic obstructive pulmonary disease (AECOPD) remains unclear. To evaluate whether baseline FeNO levels predict corticosteroid treatment efficacy in hospitalized AECOPD patients. A total of 116 AECOPD patients were enrolled and stratified into high-FeNO (>25 ppb, n=45) and low-FeNO (≤25 ppb, n=71) groups. All received standard treatment including bronchodilators, anti-infectives, oxygen and 7-day intravenous corticosteroids. Biomarkers (CRP, eosinophils), arterial blood gases and COPD Assessment Test (CAT) scores were measured before and after treatment. The high-FeNO group showed significant reductions in CRP and PaCO2 post-treatment (p<0.001), with a greater decline in CAT scores compared to the low-FeNO group (p<0.001). Eosinophil counts differed significantly between groups at baseline and post-treatment. Baseline FeNO >25 ppb predicts better corticosteroid responsiveness in AECOPD, supporting its utility as a practical biomarker for guiding steroid therapy and reducing overtreatment risks.