Natural History of Untreated Idiopathic Sudden Sensorineural Hearing Loss.

OBJECTIVE:Although corticosteroids and other treatments for idiopathic sudden sensorineural hearing loss (ISSNHL) have been described, understanding its prognosis without intervention provides valuable information for patient management. The objective of this study is to provide a comprehensive, quantitative statistical analysis of the natural history of untreated idiopathic sudden sensorineural hearing loss (ISSNHL). STUDY TYPE AND DESIGN:A systematic review and meta-analyses. METHODS:Two independent searches of PubMed, Scopus, Web of Science, and Cochrane Library databases up to June 30, 2022, were performed. Adults with idiopathic sudden sensorineural hearing loss who received placebo or were untreated and had audiometric outcome measures in all study types were reviewed. These data indicative of the natural history of ISSNHL were analyzed, as were study characteristics related to risk of bias. Heterogeneity as assessed via I2 and random effects analyses were performed. RESULTS:Six studies meeting the inclusion criteria yielded 319 untreated patients whose natural history could be assessed. Heterogeneity among studies was moderate, with a variety of reported outcomes. A hearing improvement of at least 30 dB HL was observed in 36% (95% CI 0.28-0.44) of untreated patients, and of at least 10 dB HL was observed in 70% (95% CI 0.57-0.82) of untreated patients at 3 months. The mean hearing gain among untreated patients was 24.0 dB HL (95% CI 2.65-45.37) at 2-3 months. CONCLUSIONS:The observed natural history of ISSNHL suggests that patients can regain some hearing without active treatment. In the absence of future studies collecting prospective natural history data from untreated or placebo-treated ISSNHL patients, the data presented here provide the best available historical control data for reconsideration of results in past ISSNHL studies, as well as a roadmap for design and interpretation of future ISSNHL treatment clinical trials. Furthermore, knowing there is a statistically significant mean hearing gain of 24.0 dB HL in the untreated/placebo group provides an ethical basis for future placebo study of ISSNHL. The current status on ISSNHL management calls for a multi-institutional, randomized, double-blind placebo-controlled trial with validated outcome measures to provide science-based treatment guidance. Laryngoscope, 134:S1-S15, 2024.