Type 2 Diabetes Mellitus and Hearing Loss: A Prisma Systematic Review and Meta-Analysis.

Objective: To conduct a systematic review and meta-analysis to assess the association between type 2 diabetes and hearing loss.

Data Sources: Search conducted in PubMed and Scopus databases for articles published between January 2019 and April 2024.

Review Methods: Quality assessment and risk of bias analysis were conducted using the Newcastle-Ottawa scale, and meta-analyses of pooled data were performed with Cochrane's Review Manager.

Results: From 8354 initially identified articles, 17 met the inclusion criteria. The prevalence of hearing loss in patients with type 2 diabetes range from 40.6% to 71.9%, which was significantly higher than in controls (odds ratio [OR]: 4.19; 95% confidence interval [CI]: 1.22-14.37). The mean pure-tone audiometric thresholds of the diabetic group were 3.19 dB higher (95% CI: 1.08-5.19) and were higher for both low frequencies (1.11 dB, 95% CI: 0.62-1.57) and, more severely, for high frequencies (2.3 dB, 95% CI: 1.97-2.63). Patients with moderate (0.57%, 95% CI: 0.1-1.05) and severe-to-profound (0.95%, 95% CI: 0.02-1.87) hearing loss had higher mean HbA1c levels than controls. The prevalence of hearing loss was significantly higher among patients with a diagnosis of diabetes for more than 10 years (OR 2.07, 95% CI: 1.45-2.94). The gender of diabetic patients was found to have no influence.

Conclusion: The prevalence of hearing loss among individuals with type 2 diabetes ranges from 40.6% to 71.9%. Compared to the control group, the risk of hearing loss is 4.19 times higher and is predominantly observed at higher frequencies. The duration of diabetes and HbA1c levels are significant factors in the prevalence of hearing loss.