Hearing loss in type 1 diabetes: Are we facing another microvascular disease? A meta-analysis

Evidence shows type 1 diabetes(T1D) leads to vascular damage and neuropathy. The purpose of this study was to perform a systematic review and a meta-analysis to assess the evidence of the effects of T1D on hearing function.

Three electronic databases were used. The articles were independently reviewed by two authors using predefined inclusion criteria to identify eligible studies. They were then classified as high or low methodological quality. Meta-analysis was performed on pooled data of hearing loss(HL) prevalence, pure tone audiometry(PTA), otoacoustic emissions(OAE) and auditory brainstem response(ABR).

Twenty-one articles fulfilled the inclusion criteria. In all studies, HL was defined as pure tone greater than 20 dB in at least one frequency. The prevalence of HL ranged between 5.17% and 48% for diabetics, which was higher than in controls which ranged between 0% à 40% (OR = 7.7, 95% CI 3.32-17.98, p < 0.05 and I² = 40%). The tendency of mean thresholds of PTA was higher in diabetics than in controls, with results being statistically significant at 250, 500 and 1000 Hz. OAE were significantly lower in diabetic patients. ABR latencies were longer in T1D group compared to controls and were statistical significant.

Patients with T1D have a significantly greater prevalence of HL compared to the control group. These damages could be compared to other microvascular diseases. Further studies are needed to assess whether hearing testing should be considered as a part of the screening process in T1D patients and therefore, secondary preventive treatment may be warranted as well.