Impact of smoking on sinus CT findings across subtypes of chronic rhinosinusitis: A retrospective study

BACKGROUND: Smoking is a recognized risk and aggravating factor for chronic rhinosinusitis (CRS), yet its impact on radiological severity remains inconsistent. We examined whether the association between smoking and computed tomography (CT) severity differed by CRS subtype: eosinophilic CRS (ECRS) vs. non-eosinophilic CRS (non-ECRS). METHODS: We conducted a single-center retrospective cross-sectional study of adults (≥20 years) diagnosed with CRS who underwent sinus CT. Secondary rhinosinusitis and prior sinus surgery were excluded. The primary outcome was the Lund-Mackay score (LMS, 0-24). Within each subtype, we compared LMS among never, former, and current smokers and performed multivariable linear regression adjusted for age, sex, body mass index (BMI), allergic rhinitis and medication use. RESULTS: Of 496 screened patients, 235 were analyzed after exclusion (ECRS, 121 [51.5%]; non-ECRS, 114 [48.5%]). In the ECRS, LMS did not differ among never, former, and current smokers (median: 12, 12, and 11, respectively). In the non-ECRS group, current smokers had significantly higher LMS than never and former smokers (median 9 vs. 3 and 3; never vs. current, p < 0.001; former vs. current, p = 0.009), with no significant difference between never and former smokers (p = 0.745). After adjustment, current smoking was independently associated with higher LMS in the non-ECRS group (adjusted β 4.99, 95% CI 3.04-6.95; p < 0.001) but not in the ECRS group. CONCLUSION: The radiological impact of smoking on CRS appears to be subtype-dependent. Current smoking is associated with higher CT severity in non-ECRS but not in ECRS, suggesting a subtype-tailored prioritization of smoking cessation interventions.