Clinical and Immunohistochemical Evaluation of Peripheral Neuropathy in Diabetic Patients

Background Diabetic peripheral neuropathy is a prevalent and severe complication of diabetes that significantly impacts a patient’s quality of life. Early diagnosis through clinical examination and intraepidermal nerve fiber density (IENFD) measurement is essential. However, limited healthcare access and specialists, and uncontrolled blood glucose levels increase the risk of lower limb amputation. This is the first study in Mongolia to evaluate epidermal nerve fibers for the assessment of DPN. Methods and Results Thirty diabetic patients (20–74 years) underwent foot examination and skin punch biopsies. The skin biopsies were analyzed by immunohistochemistry using protein gene product 9.5 (PGP 9.5) antibody to quantify the total IENF. Among participants, 94% had poor glycemic control, were diagnosed with 26.7% mild, 40% moderate, and 16.7% severe neuropathy. The average number of epidermal nerve fibers in 1 mm was 7.87 ± 4.72, reflecting an 86.7% reduction. DPN showed a strong correlation with both diabetes duration (V = 0.876, p < 0.0001) and HbA1C level (V = 0.760, p < 0.0001). The specificity and sensitivity of the immunohistochemistry method were 40% and 92%, respectively. Conclusion DPN severity is associated with diabetes duration and poor glycemic control. IENFD highlights a more objective measure of small nerve fiber reduction, and combining it with clinical assessment provides a comprehensive and accurate approach for diagnosing DPN. Early detection of DPN, strict glycemic control, and integration of IENFD into diagnostic protocols are urgently needed, particularly in developing countries such as Mongolia.