Assessment of the Relationship Between Small Airways Dysfunction and Neutrophilic Inflammation in Exacerbated Chronic Obstructive Pulmonary Disease Patients

Abstract

Background: Small-airway dysfunction (SAD) is an under-recognized but significant aspect of chronic obstructive pulmonary disease (COPD). Neutrophilic inflammation also plays a significant part in exacerbations of COPD, although the connections between neutrophilic inflammation and small-airway impairment during such exacerbations are poorly understood. The aim of this study was to evaluate the relation between neutrophilic inflammation and SAD in AECOPD patients.

Material and Methods: This was an analytical cross-sectional study of 88 patients suffering from AECOPD. Demographic and clinical data were collected, followed by pulmonary function testing and laboratory studies in Mardan Medical Complex, from February 2023 to July 2023. The main indicator of small-airway function was forced expiratory flow at 25-75% of forced vital capacity (FEF₂₅-₇₅%). The absolute neutrophil count, the neutrophil percentage, the neutrophil-to-lymphocyte ratio (NLR), and the C-reactive protein (CRP) were evaluated. Correlation and multivariable logistic regression analyses were carried out.

Conclusion: SAD was found in 65 (73.9%) patients. FEF₂₅-₇₅% was inversely correlated with absolute neutrophil count (p<0.001), neutrophil percentage (p<0.001), NLR (p=0.001), and CRP (p=0.008). Pulmonary function and neutrophilic inflammatory markers were significantly higher in patients with SAD. Absolute neutrophil count (p=0.018) and NLR (p=0.036) were still independently associated with SAD on multivariable analysis.

Conclusion: Small-airway dysfunction was common in AECOPD and was significantly associated with increased neutrophilic inflammation. The results indicate that the peripheral airway impairment may interact with neutrophilic inflammatory activity during COPD exacerbations.

Keywords: COPD; acute exacerbation; small-airway dysfunction; neutrophils