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 (Delta), 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 (Delta 15.3 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, 2024