Chronic rhinosinusitis association with small airway disease: Inflammatory biomarkers and lung function using impulse oscillometry

OBJECTIVE: This study aimed to evaluate the correlation between CRS-related biomarkers and disease severity with spirometric and impulse oscillometry parameters in patients with and without asthma. METHODS: We conducted a cross-sectional study involving 52 adult patients with CRS with nasal polyps. All participants underwent clinical evaluation, SNOT-22 scoring, nasal endoscopy, Lund-Kennedy (LK) and Lund-Mackay (LM) scores, blood sampling for eosinophils and IgE, skin prick testing, spirometry, and impulse oscillometry testing. Correlations among upper airway severity, inflammatory markers, and lung function parameters were analyzed using Spearman's rank correlation coefficient. RESULTS: Patients had preserved mean FVC (Forced Vital Capacity) and FEV1 (Forced Expiratory Volume in 1 s) values, as well as FEV1/FVC (mean 73.6%) and FEF25-75%. Impulse oscillometry showed increased Resonant Frequency and area of reactance. SNOT-22 correlated negatively with FEV1 and FVC, and positively with Z5 (total impedance). Eosinophils correlated negatively with FEV1, FEV1/FVC, and FEF25-75%, and positively with AX (reactance area) and peripheral resistance. No significant correlations were found with total IgE or aeroallergen sensitization. CONCLUSIONS: Impulse oscillometry parameters were similar to those reported in the literature for small airway disease. This study demonstrated a negative correlation between spirometry parameters and blood eosinophil count. There was also a negative correlation between the severity of CRS symptoms and FEV1 and FVC. LEVEL OF EVIDENCE: Oxford Centre for Evidence-Based Medicine 2011. LEVELS OF EVIDENCE: Level 4.