Long-Term Risk of Progression From Unilateral to Bilateral Méniere's Disease: A Systematic Review and Meta-Analysis

To evaluate the overall risk of conversion from unilateral to bilateral Méniere's disease (MD), the time interval from initial diagnosis to conversion, and any risk factors or audiometric trends associated with this process.

Medline, Embase, Cochrane Library, Scopus, Web of Science, and ClinicalTrials.Gov.

This review was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies reporting longitudinal progression of unilateral to bilateral MD were included. Random-effects meta-analyses were performed to evaluate the proportion of cases that converted and the mean time to conversion, and a narrative synthesis described risk factors and audiometric data.

A total of 11 studies met the inclusion criteria. For overall conversion risk, meta-analysis of the 9 relevant studies (n = 1583) yielded a risk of 13% (95% CI, 12-15%). Mean time to conversion was 8.2 years (95% CI, 5.9-10.6; I2 = 46%), and a combined Kaplan-Meier analysis revealed a prolonged distribution of conversions including 10% that converted 20 years or later after initial diagnosis. Risk factors and audiometric data were sparsely reported, but there may be a correlation between conversion risk and first-sided ear surgery (protective), history of tympanic membrane perforation, and baseline hearing loss in the unaffected ear.

There is a significant risk of conversion from unilateral to bilateral MD that must be taken into account when considering ablative treatment options, even late into its course. Further work will be required to better characterize risk/protective factors and audiometric trends.