Spontaneous recovery rate of idiopathic sudden sensorineural hearing loss: A systematic review and meta-analysis.

PURPOSE: Steroids comprise the mainstay of treatment for idiopathic sudden sensorineural hearing loss (ISSNHL). Since steroidal treatment was integrated to clinical practice guidelines, newly published no-treatment or placebo arms in clinical trials are scarce. To evaluate the effectiveness of steroidal treatment ± hyperbaric oxygen therapy, the data should be compared to spontaneous recovery. The aim of this paper is to find the most accurate spontaneous recovery rate, in the light of which, other treatment modalities should be judged. MATERIALS AND METHODS: Eligible studies published until July 2021 were identified through systematic searches of 'PubMed', 'Web of Science' and 'Google Scholar'. Retrospective studies and randomised/non-randomised control trials involving only adult participants (≥18 years) with ISSNHL, and placebo/no treatment were included. Only articles that used the American Academy of Otolaryngology-Head and Neck Surgery's diagnostic criteria for ISSNHL were included. RESULTS: 942 records initially identified, 166 duplicates and 753 articles were excluded based on article subject, title, and abstract. The full texts of 13 articles were reviewed. Seven studies were included for qualitative synthesis, five papers included in quantitative synthesis. 180 ears were included in pooled statistics. The pooled spontaneous recovery was 60.28% (95% confidence interval [CI] = 38.88%-79.94%) with a heterogeneity of 86.0% (95% CI = 69.4%-93.6%). CONCLUSIONS: Spontaneous recovery of ISSNHL should not be over-looked, as it may be close to 60%. This may have both clinical and research implications.