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.