Prognosis of Bilateral Sudden Sensorineural Hearing Loss: A Systematic Review and Meta‐Analysis

Objectives To comprehensively examine the characteristics and prognosis of bilateral sudden sensorineural hearing loss (BSSHL) and its subtypes compared to unilateral sudden sensorineural hearing loss (USSHL). Data Sources PubMed, Scopus, and CINAHL. Review Methods Databases were searched from inception to December 5, 2023, for studies reporting patient characteristics and audiometric outcomes for BSSHL and its simultaneous (Si‐BSSHL) and sequential (Se‐BSSHL) subtypes. Meta‐analysis of continuous measures, proportions (%), mean differences (Δ), and odds ratio (OR) were performed. Results Eleven studies were included, consisting of 368 patients with BSSHL and 2,705 patients with USSHL. The pooled prevalence among all SSHL cases was 88.1% (95% CI: 81.2%–93.6%) for USSHL and 11.9% (95% CI: 6.4% to 18.8%) for BSSHL. PTA improvement following treatment with steroids was significantly worse in patients with BSSHL (Δ15.3 dB; 95% CI: 14.6 to 15.9; p < 0.0001) compared to patients with USSHL. There was no significant difference in post‐treatment PTA improvement between the BSSHL subtypes. Patients with Si‐BSSHL were significantly less likely to have an idiopathic etiology (OR: 0.4; 95% CI: 0.2 to 0.8; p = 0.01) and significantly more likely to have an autoimmune disease etiology (OR: 27.4; 95% CI: 2.2 to 336.1; p = 0.01), comorbid cardiovascular disease (OR: 2.3; 95% CI: 1.1 to 5.1; p = 0.03), and comorbid hypertension (OR: 2.5; 95% CI: 1.6 to 3.8; p < 0.0001) compared to patients with USSHL. Conclusions BSSHL is a considerably rarer form of SSHL with worse prognosis compared to USSHL. BSSHL, and Si‐BSSHL in particular, has significantly greater associations with systemic pathologies compared to USSHL. Laryngoscope , 134:3883–3891, 2024