Insulin resistance as a predictor of sensory neuropathy in prediabetes

Abstract

Objective: The aim of this study is to assess the association of insulin resistance with sensory neuropathy in prediabetes. Materials and Methods: Fasting serum insulin levels were measured and the homeostatic model assessment of insulin resistance (HOMA-IR) was calculated in all patients. These were compared in prediabetic patients having sensory neuropathy to those who did not have sensory neuropathy as determined by vibration perception thresholds (VPTs) measured using Digital Biothesiometer. Furthermore, direct correlation between insulin resistance and VPTs was checked. Results: A total of 60 prediabetic cases were included in this study. Among the study population, the age distribution ranged from 35 years to 60 years with the mean age of 48.68 years. Male and female formed 65% and 35% of the study population, respectively. The maximum fasting serum insulin levels were 21.8 mIU/L, and the minimum fasting serum insulin levels were 3.5 mIU/L, with the mean value being 10.61 ± 4.99 mIU/L. The maximum HOMA-IR was 6.4, and the minimum was 0.986, with the mean value being 2.81 ± 1.37. Among all the prediabetic patients, 43.3% of patients had neuropathy according to VPTs measured using Biothesiometer. T-test analysis suggests that mean fasting serum insulin levels (P = 0.026) and HOMA-IR (P = 0.032) were significantly higher in patients with neuropathy than patients without neuropathy. VPTs were found to have statistically significant positive correlation with fasting serum insulin levels (Pearson correlation coefficient = 0.317 [R], 0.296 [L];P = 0.013 [R], 0.022 [L]) and HOMA-IR (Pearson correlation coefficient = 0.299 [R], 0.281 [L];P = 0.02 [R], 0.03 [L]). Conclusion: Insulin resistance, quantified with the help of the index, HOMA-IR, has an important role in the development of this sensory neuropathy.