Classification of chronic rhinosinusitis in Taiwan: A comprehensive analysis based on European Position Paper on rhinosinusitis and nasal polyps (EPOS) 2020.

Background: Chronic rhinosinusitis (CRS) is characterized by heterogeneous clinical presentations and underlying pathophysiology. The European Position Paper on Rhinosinusitis and Nasal Polyps (EPOS) 2020 introduced a new classification system categorizing CRS, moving away from with (CRSwNP) and without polyps (CRSsNP). This study applies the EPOS 2020 framework to categorize CRS patients in Taiwan, focusing on eosinophilic CRS (eCRS) and its clinical implications in this population.

Methods: A retrospective cross-sectional study analyzed medical records of CRS patients who underwent endoscopic sinus surgery at a Taiwanese medical center from January 1 to December 31, 2023. Patients were classified per EPOS 2020 criteria using clinical history, nasal endoscopy, and CT scans. Demographic data, symptom severity (Sino-Nasal Outcome Test, SNOT-22), olfactory function (Taiwan Smell Identification Test, TWSIT), and inflammatory markers (blood eosinophil count, IgE) were assessed.

Results: Of the cohort (n = 335), 69.8 % were classified as primary CRS, with eCRS accounting for 33.4 % of cases. Among CRSwNP patients, eCRS prevalence was 56.2 %, compared to 19.0 % in CRSsNP patients. eCRS patients exhibited significantly higher eosinophil counts, CT Lund-Mackay scores, and worse olfactory function compared to non-eCRS counterparts (p < 0.01).

Conclusions: This study underscores the predominance of eCRS among CRS patients in Taiwan and its association with severe disease burden, particularly in CRSwNP. The findings support the utility of EPOS 2020 in characterizing CRS phenotypes and guiding personalized treatment strategies. This research contributes valuable insights into CRS epidemiology in Asia, advocating for further exploration into regional variations and therapeutic approaches.