Hubungan antara Kadar Nerve Growth Factor dengan Parameter Metabolik dan Skor Michigan Neuropathy Screening Instrument pada Pasien Diabetes Melitus Tipe 2

Abstract

Background: Diabetic peripheral neuropathy (DPN) is a common complication of type 2 diabetes mellitus, with complex pathophysiology involving chronic hyperglycemia, insulin resistance, oxidative stress, and inflammation. Nerve Growth Factor (NGF) plays a crucial role in maintaining peripheral nerve integrity, and its concentration is thought to reflect the degree of nerve damage. The relationship between NGF levels, neuropathy scores, and insulin resistance remains unclear. Objective: To evaluate the association between Nerve Growth Factor (NGF) levels, metabolic parameters, and Michigan Neuropathy Screening Instrument (MNSI) scores in patients with type 2 diabetes mellitus. Methods: A cross-sectional analytical study was conducted involving 77 patients with type 2 diabetes mellitus, divided into two groups based on the presence of diabetic peripheral neuropathy (DPN), as assessed using MNSI A and/or MNSI B scores. Serum levels of Nerve Growth Factor (NGF), Homeostasis Model Assessment for Insulin Resistance (HOMA-IR), Homeostasis Model Assessment for Beta-cell function (HOMA-β), hemoglobin A1c (HbA1c), fasting blood glucose (FBG), and 2-hour postprandial glucose (2HPP) were measured. Correlation analyses were performed to assess the association between NGF levels and metabolic parameters. Results: All 77 patients with type 2 diabetes mellitus had abnormal NGF levels (<11 pg/mL). In the overall sample, NGF levels showed a significant negative correlation with HOMA-IR and HOMA-β (p = 0.021; r = –0.263 and p = 0.005; r = –0.316, respectively). Among the 37 patients diagnosed with diabetic peripheral neuropathy (11 positive on MNSI A, 10 on MNSI B, and 16 on both A and B), a significant negative correlation was also observed between NGF and HOMA-β (p = 0.009; r = –0.425). No significant correlation was found between NGF and FBG, 2HPP, or HbA1c in the DPN group. NGF levels were significantly associated with MNSI part B scores (p = 0.032), but not with part A or the combined MNSI score. Conclusion: A significant negative correlation was found between NGF levels and both HOMA-IR and HOMA-β, indicating the involvement of insulin resistance in the reduction of NGF levels among patients with type 2 diabetes mellitus. NGF levels were also significantly associated with the MNSI part B score, confirming that physical examination more accurately reflects neuropathic changes related to NGF levels. No significant associations were observed between NGF levels and HbA1c, FPG, 2 h PP.