The efficacy of statins as otoprotective agents: A systematic review.

OBJECTIVE: This systematic review examined the current literature, summarized research findings and identified research gaps regarding the efficacy of statins on audiological outcomes. METHODS: Systematic search of electronic databases and grey literature was performed. Eligibility criteria was the study of a statin drug with report of audiological outcomes such as hearing, tinnitus, or balance in either human or animal studies. Data extraction and quality assessment were performed by two independently researchers. The characteristics of the study and research findings were collated and summarized. A narrative synthesis was conducted. Meta-analysis was not possible due to heterogeneity of the included studies. RESULTS: Analysis of searches yielded 17 studies meeting the criteria. Included studies had variable drug type and dosage, outcome measures, and associated inner ear conditions. Most animal experiments showed promising audiological outcomes after statin treatment, demonstrated by the results of auditory brain stem response, distortion product otoacoustic emissions, and inner ear histology. However, no clear effect can be discerned in human trials due to the mixed results, and heterogeneity in research methodology and quality. Audiological outcomes were not always correlated with cholesterol levels. CONCLUSIONS: Statins remain a potential candidate as otoprotective agents which warrant further investigation.