Comparison of Audiometric Outcomes Following Acute Labyrinthitis

Background and Objectives: Labyrinthitis is an inflammatory inner ear disorder often resulting in acute vertigo and hearing loss. While typically self-limiting, some cases lead to persistent deficits. This study examined incidence trends of acute labyrinthitis before and after 2020 and compared hearing outcomes between these periods. Materials and Methods: This retrospective cohort study included 126 patients diagnosed with acute labyrinthitis at a tertiary medical center between January 2014 and May 2024. Patients were divided into pre-2020 (2014-2019) and post-2020 (2020-2024) cohorts. Poisson regression analyzed incidence trends, while audiometric outcomes were compared in 79 patients with complete 3-month follow-up data. Hearing recovery was assessed using pure-tone averages (PTA) across 500-4000 Hz, and predictors of persistent impairment were identified through multivariable logistic regression. Results: The cohort had a mean age of 47.8 years with female predominance (63.5%). Annual case counts increased significantly post-2020 (19.8 vs. 6.5 cases/year; CRR 3.05, 95% CI 2.07-4.57, p < 0.001). Substantial hearing improvement occurred across all frequencies (median AC improvement 13.8 dB). Hearing recovery was comparable between periods, with similar PTA improvements (-16.7 vs. -15.3 dB, p = 0.73) and equivalent distributions across World Health Organization (WHO) hearing categories (p = 0.64). Baseline hearing level was the strongest predictor of persistent impairment (OR 1.56 per 5 dB increase, 95% CI 1.25-1.95, p < 0.001), while age, sex, and diagnostic period showed no significant association. Among post-2020 patients, only 12.6% had confirmed coronavirus disease 19 (COVID-19), and no reliable association with hearing outcomes could be established due to substantial missing data. Conclusions: A significant increase in hospital-diagnosed labyrinthitis cases occurred following 2020, yet hearing outcomes at 3-month follow-up remained consistent with the pre-pandemic period. Baseline hearing level was the primary determinant of recovery, unaffected by demographic factors or diagnostic period. These findings suggest that while pandemic-related factors may have influenced case frequency, they did not alter auditory prognosis or recovery patterns.