Abstract
BACKGROUND: Diabetes mellitus is a serious, chronic metabolic disorder associated with microvascular and macrovascular complications that affect the cardiac, renal, ophthalmic, cerebral, and peripheral systems. Similar complications can also occur in the structures of the inner ear. OBJECTIVES: This study aimed to assess the hearing function of patients diagnosed with T2DM and to investigate the relationship between hearing function and the stage of diabetic retinopathy. METHODS: This prospective, single-center, cross-sectional, and case-control study included 30 healthy controls (Group 1) and 90 patients with T2DM [30 without retinopathy (Group 2), 30 with non-proliferative diabetic retinopathy (Group 3), and 30 with proliferative diabetic retinopathy (Group 4)] aged 40 to 60 years. The best-corrected visual acuity and audiological tests, including pure tone audiometry (PTA) and high frequency audiometry (HFA), were performed. RESULTS: A statistically significant difference was observed at all frequencies (for all, p < 0.001), except for 125 Hz (for 125 Hz, p = 0.075). The median PTA values were 13.75 (min-max: 5-31.2) in Group 1, 20 (min-max: 10-37.5) in Group 2, 16.87 (min-max: 8.7-42.5) in Group 3, and 24.37 (min-max: 12.5-56.25) in Group 4. A multiple comparisons analysis for PTA showed a statistically significant difference between Group 1 and Group 4 (p < 0.001). The mean HFA values were 32.23 ± 12.27 in Group 1, 50.23 ± 12.80 in Group 2, 53.47 ± 10.75 in Group 3, and 62.63 ± 12.52 in Group 4. The HFA values were significantly lower in Group 1 compared to the other groups (p < 0.001). In pairwise comparisons, p = 0.730 for Group 2 vs. Group 3, p = 0.001 for Group 2 vs. Group 4, and p = 0.021 for Group 3 vs. Group 4. CONCLUSIONS: It was observed that T2DM patients were at risk for developing hearing impairment, and sensorineural hearing impairment increased as the DR stage progressed, particularly in high frequencies. These results suggest a hearing evaluation in the screening of DR patients.