Sudden Sensorineural Hearing Loss and Metabolic Syndrome: A Systematic Review and Meta-analysis

OBJECTIVE: The objective of this systematic review and meta-analysis is to examine the association between sudden sensorineural hearing loss (SSNHL) and risk of metabolic syndrome (MetS), and the association between MetS and prognosis of SSNHL. DATABASES REVIEWED: We systematically searched MEDLINE, Embase, and Cochrane Central Register electronic databases from their dates of conception to February 4, 2020. METHODS: We included observational studies analyzing 1) the prevalence of MetS among SSNHL patients, or 2) the prognosis of SSNHL patients in MetS patients. A standardized form was completed in duplicate extracting data on study characteristics, participant demographics, and SSNHL outcome or recovery measures. Random-effects meta-analyses were performed pooling odds ratios using the generic inverse method. Risk of bias was assessed using the Newcastle Ottawa Scale. RESULTS: Three studies examining the prevalence of MetS among patients with SSNHL (11,890 total participants; 3,034 SSNHL participants) yielded a significantly increased risk of MetS among SSNHL, with a pooled odds ratio of 1.88 (95% CI, 1.01-3.50). Three studies examining the association of SSNHL prognosis in patients with MetS (608 SSNHL participants, 234 concomitant SSNHL, and MetS participants) demonstrated that SSNHL patients with MetS were significantly more likely to have poorer recovery compared to SSNHL patients without MetS (pooled odds ratio 2.77; 95% CI, 2.33-3.28). CONCLUSION: Our findings suggest an association between prevalence of MetS and SSNHL, as well as poorer prognosis of SSNHL in patients with concomitant MetS.