Whole blood viscosity and its association with the presence and severity of hearing loss and other microangiopathies in Indian patients with type 2 diabetes mellitus.

Background/aims: Although studies correlating idiopathic sensorineural hearing loss (SNHL) to whole blood viscosity (WBV) have been conducted, no such study has been done in diabetic patients in whom WBV is said to be altered. Therefore, we aimed to investigate the potential association between calculated WBV and the presence and severity of SNHL and other microangiopathies in Indian patients with type 2 diabetes mellitus (T2DM).

Methods: A cross-sectional study was carried out in the Kasturba Medical College (KMC) group of hospitals among individuals who were older than 18 years and had T2DM. The included patients underwent pure-tone audiometry, ophthalmoscopy, monofilament test, and routine blood investigations for diabetes. WBV was derived using hematocrit and total protein with a validated formula.

Results: Of the total 60 participants, 73.3% had SNHL, which was predominantly bilateral and moderate. There was a statistically significant association between glycemic control and the degree of SNHL. The associations between SNHL and HbA1C levels and random plasma glucose were both statistically significant (P = .001). The statistical association between WBV and the degree of SNHL was not significant (P = .056). Although higher mean blood viscosity was noted in individuals with diabetic retinopathy and neuropathy than those without, the associations between blood viscosity and the presence of retinopathy, neuropathy, and nephropathy were not statistically significant (P = .238, P = .621, and P = .656; respectively). Finally, the associations between WBV and glycemic control were also not significant (P = .652 for random plasma glucose and P = .928 for HbA1C).

Conclusion: This study concludes that SNHL is highly prevalent in diabetes, and poor glycemic control is associated with its worsening. Elevations in WBV, if present, are not affected by poor glycemic control and do not appear to significantly contribute to the development of complications of the microvasculature in T2DM.