Distribution and Determinants of Peripheral Neuropathy Among Patients With Type 2 Diabetes Mellitus and Its Association With Insulin Resistance: A Cross-Sectional Study Using Nerve Conduction Studies and Shear-Wave Elastography

Abstract

Background: Diabetic peripheral neuropathy (DPN) is a common complication of type 2 diabetes mellitus (T2DM). Although chronic hyperglycemia is traditionally considered a major contributor, increasing evidence suggests that insulin resistance and metabolic dysfunction may also play an important role. This study evaluated the distribution of peripheral neuropathy among patients with T2DM and examined its association with insulin resistance assessed using the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), along with structural nerve changes assessed by shear-wave elastography (SWE).
Methods: A hospital-based cross-sectional analytical study was conducted from May 2024 to October 2025 among 100 adults aged 18–65 years with T2DM. Participants underwent clinical assessment, biochemical evaluation, nerve conduction studies (NCS), and SWE of peripheral nerves. Fasting glucose and fasting insulin were used to calculate HOMA-IR. NCS was used to classify participants according to the presence or absence of electrophysiological neuropathy. SWE was performed on the posterior tibial and median nerves. Statistical analysis included comparative tests, correlation analysis, and multivariable logistic regression.
Results: The mean age of participants was 50.1 ± 8.6 years, and 51% were male. The mean duration of diabetes was 8.9 ± 4.4 years. The mean HOMA-IR was 6.0 ± 2.1. Abnormal NCS findings were observed in 83% of participants. Participants with abnormal NCS had significantly higher HOMA-IR than those with normal NCS (6.10 ± 2.13 vs. 3.03 ± 0.85, p<0.001). Median nerve stiffness was also significantly higher among participants with abnormal NCS (101.20 ± 21.47 vs. 51.64 ± 12.30 kPa, p<0.001). HOMA-IR showed a strong inverse correlation with motor nerve conduction velocity (r = −0.78, p<0.001) and a positive correlation with median nerve stiffness (r = 0.68, p<0.001). Median nerve stiffness was strongly inversely correlated with motor conduction velocity (r = −0.85, p<0.001). In multivariable logistic regression, HOMA-IR remained significantly associated with abnormal NCS (OR 5.53, 95% CI 1.51–20.46; p=0.010), whereas median nerve stiffness, diabetes duration, and HbA1c were not independently significant.
Conclusion: Peripheral neuropathy was frequent among the studied patients with T2DM. Higher insulin resistance was strongly associated with electrophysiological evidence of neuropathy and structural nerve abnormalities. These findings suggest that insulin resistance may represent an important metabolic factor associated with diabetic peripheral nerve dysfunction. Longitudinal studies are required to establish temporal and causal relationships.