Population-based differences in otosclerosis: a dual-center study of radiological and audiological comparison in Chinese and Swiss patients.

PURPOSE: To compare the clinical, radiological, and audiological features of otosclerosis across two tertiary centers in Switzerland and China. METHODS: We included 478 adult patients (540 operated ears) who underwent primary stapes surgery for otosclerosis between 2015 and 2023 at a Swiss hospital (LH) and a Chinese hospital (PH). All patients underwent preoperative high-resolution CT and pure-tone audiometry. A semiquantitative CT scoring system was used to assess involvement at four anatomical subsites. Pre- and postoperative audiometric data were compared, and associations between CT findings and hearing outcomes were evaluated using correlation and regression analyses. RESULTS: Patients from PH were significantly younger, with a less balanced age distribution. Antefenestral and footplate CT scores were significantly higher in the LH group. PH patients showed worse preoperative air conduction (AC) thresholds. Preoperative bone conduction (BC) thresholds correlated modestly with regional and total CT scores. Postoperative BC and AC thresholds were also weakly associated with total and cochlear CT scores. Postoperative AC thresholds and ABG were significantly better in the LH group. Logistic regression identified hospital site and preoperative ABG as significant predictors of achieving ABG ≤ 10 dB HL. CONCLUSION: This dual-center study reveals distinct clinical profiles of otosclerosis between Chinese and Swiss patients. Although operated at a younger age, Chinese patients had worse hearing but milder CT changes. Both groups improved after surgery, yet complete ABG closure was more frequent in the Swiss group. This study emphasizes the need for population-sensitive treatment strategies and expectations in otosclerosis.