Short term exacerbation risk and exhaled nitric oxide in COPD

Exacerbations of chronic obstructive pulmonary disease (COPD) significantly impact morbidity and healthcare utilization. Identifying biomarkers predictive of exacerbation risk can optimize management strategies. We evaluated the role of baseline fractional exhaled nitric oxide (F_ENO) as a predictor of moderate and severe exacerbations over 90 days.

A prospective cohort study included COPD patients attending pulmonology clinics. Patients were stratified based on baseline F_ENO levels: F_ENO <20 ppb and FENO ≥20 ppb. The primary outcome was time-to-first exacerbation, analysed using Kaplan-Meier survival curves and Cox proportional hazards models. Secondary outcomes included differences in baseline characteristics and hazard ratios (HR) for severe exacerbations.

A total of 322 patients were included (220 with F_ENO <20 ppb, 102 with F_ENO ≥20 ppb). Kaplan-Meier analysis showed significantly shorter survival time without moderate/severe exacerbations in those with high F_ENO. Cox regression demonstrated a 3.01-fold increased risk of moderate/severe exacerbations in high F_ENO (HR: 3.01, 95 % CI: 1.83-4.93; p < 0.001). For severe exacerbations, those patients exhibited a non-significant trend toward increased risk (HR: 2.49, 95 % CI: 0.91-6.86; p = 0.058).

Elevated F_ENO (≥20 ppb) is associated with increased short-term risk of moderate and severe COPD exacerbations. These findings highlight F_ENO as a potential biomarker for early risk stratification and tailored interventions in COPD patients.