Early hearing improvement predicts the prognosis of idiopathic sudden sensorineural hearing loss

Purpose To determine pre- and post-treatment factors that are useful for predicting the prognosis of hearing improvement in idiopathic sudden sensorineural hearing loss (ISSHL). Methods This retrospective study included 332 patients with ISSHL. Patients received intravenous steroid treatment (prednisolone sodium succinate; 120 mg/day followed by dose tapering). Complete recovery of hearing levels was defined as a final pure-tone audiometry of ≤ 20 dB HL or the same level as the contralateral ear. Patients’ age; sex; side of hearing loss; initial hearing level; days from onset to treatment; presence of vertigo, diabetes, and hypertension; and hearing improvement on days 3–4 and 6–7 after treatment initiation were analyzed as potential prognostic factors. Results Overall, 109 patients (32%) had complete recovery. Results of the multivariate logistic regression model identified age (odds ratio [OR] = 0.974), initial hearing level (OR = 0.949), vertigo (OR = 0.409), and hearing improvement on days 6–7 after treatment initiation (OR = 1.11) as significant independent predictors of complete recovery. Age ≥ 60 years, initial hearing level ≥ 72.5 dB HL, and vertigo contributed to poor prognosis. Patients without these three factors and a hearing improvement of ≥ 10 dB HL on days 6–7 post-treatment had a complete recovery rate of 80%. Only 1.5% of the patients with 2–3 of these factors and a hearing improvement of < 10 dB HL on days 6–7 after treatment initiation achieved complete recovery. Conclusion Age, initial hearing level, vertigo, and hearing improvement on days 6–7 after treatment initiation were independent predictors of hearing recovery in ISSHL.