Chronic Rhinosinusitis Is Associated with Lower Airway Mucus Plugging

Background: Chronic rhinosinusitis (CRS) is associated with lower airway diseases, but its relationship with mucus plugging remains unclear. We investigated the association between CRS and lower airway mucus plugging. Methods: This single-center retrospective observational study included patients who underwent paranasal sinus computed tomography and chest high-resolution computed tomography. Associations between CRS and mucus plugging were evaluated, including phenotype-stratified analyses according to eosinophilic CRS (ECRS) status. Results: Among 97 patients, 51 had CRS and 46 did not. Mucus plugging was more frequent in patients with CRS than in those without CRS (41.2% vs. 10.9%, p = 0.001), and mucus plug scores were higher in the CRS group (p = 0.002). CRS remained independently associated with mucus plugging after adjustment for asthma and bronchiectasis (adjusted odds ratio, 4.06; 95% confidence interval, 1.30–12.7; p = 0.016). Mucus plugging was more prevalent in both the non-ECRS and ECRS groups than in the non-CRS group, with no significant difference between the two CRS phenotypes. Conclusions: CRS remained associated with mucus plugging after adjustment for asthma and bronchiectasis. Mucus plugging may represent an underrecognized radiological feature of the lower airways in CRS.