Objective: To systematically review the available evidence on the association of HBA1c levels and development of sensorineural hearing loss and to quantitatively analyze the available data on HBA1c levels in patients with type 2 diabetes mellitus and sensorineural hearing loss to determine an HbA1c level that may be associated with the risk of having sensorineural hearing loss. Methods: Design: Systematic Review and Meta-analysis Eligibility Criteria: Cross-sectional studies, or cohort studies which were limited to English language that investigated the correlation of glycemic index using HBA1c and sensorineural hearing loss among adult type 2 diabetic patients which were done from January 2010 to December 2021. Studies with no published outcome, incomplete data or that were ongoing as of August 1, 2022 were also excluded. Information Sources: MEDLINE (through PubMed), Cochrane Library, Scopus, Embase (through OVID@journal), Directory of Open Access Journals (DOAJ), Google Scholar and HERDIN Plus Risk of Bias: Risk of Bias was assessed using the Guidelines for Cochrane Collaboration Synthesis of Results: Results were presented using forest plots for representation. Results: A total of 8 studies were reviewed with 2,103 participants in all. Six articles compared hearing loss incidence between diabetic and non-diabetic patients. Overall, there were a total of 881 diabetic patients and 1222 non-diabetic patients. There was a significantly lower incidence of sensorineural hearing loss in non-diabetic patients with a risk ratio of 1.89, 95% CI [1.65, 2.16]. Three articles compared the HbA1c levels of diabetic patients with or without sensorineural hearing loss. Diabetic patients without sensorineural hearing loss had significantly lower HbA1c levels compared to those with sensorineural hearing loss with mean difference of 1.04, 95%CI [0.82, 1.25]. Conclusion In conclusion, this meta-analysis showed a higher prevalence rate of sensorineural hearing loss among patients with diabetes mellitus compared to non-diabetic patients. Moreover, poor glycemic control among diabetic patients with a glycemic index based on HbA1c of more than 8.3 (6.97-9.6) is associated with sensorineural hearing loss.
diabetes mellitus ; glycemic index ; sensorineural hearing loss ; pure tone audiometry ; deafness