Small Airways Dysfunction and Neutrophilic Inflammation in Acute COPD Exacerbations: A Cross-Sectional Study

Abstract

Background: Small airways dysfunction (SAD) is a key pathological feature of COPD, particularly during acute exacerbations (AECOPD). Neutrophilic inflammation drives disease progression, but its relationship with SAD during exacerbations remains unclear. Objective: To investigate the association between systemic neutrophilic inflammatory markers and small airways dysfunction in patients hospitalized with AECOPD. Methodology: The present cross-sectional analytical study included 160 hospitalized patients with acute exacerbation of COPD. Systemic levels of inflammation were estimated with the total leukocyte count, absolute neutrophil count, percentage of neutrophils, neutrophil-lymphocyte ratio, and C-reactive protein levels at the time of admission. Results: SAD was present in 112 patients (70.0%). FEF??--?? correlated negatively with neutrophil percentage (r = -0.52), absolute neutrophil count (r = -0.48), and NLR (r = -0.55) (all p < 0.001). On multivariate analysis adjusted for age, BMI, and comorbidities, independent predictors of SAD were: NLR >3 (OR 3.12, 95% CI 1.48-6.57, p=0.003), neutrophil percentage >70% (OR 2.74, 95% CI 1.31-5.75, p=0.007), smoking >30 pack-years (OR 2.09, 95% CI 1.01-4.34, p=0.046), and GOLD stage III-IV (OR 3.68, 95% CI 1.74-7.78, p<0.001). Conclusion: Small airways dysfunction is highly prevalent during AECOPD and is independently associated with systemic neutrophilic inflammation. The neutrophil-to-lymphocyte ratio, a readily available biomarker, may help identify patients at risk of significant small airway involvement during exacerbations.