Evaluation of Leptin as a Marker of Insulin Resistance in Type 2 Diabetes Mellitus

BACKGROUND: Type 2 diabetes mellitus (T2DM) is a leading cause of mortality and morbidity worldwide, whose incidence is rapidly increasing in India. T2DM is caused by varying degrees of insulin resistance (IR) and relative insulin deficiency. Leptin, an adipokine with the primary function of regulating energy balance, is found to mediate insulin secretion and sensitivity in peripheral tissues. Hence, we aimed to determine the role of leptin in the development of IR in newly diagnosed T2DM patients. AIM: This study aims to compare the leptin levels and homeostatic model assessment-IR (HOMA-IR) levels in the study population. MATERIAL AND METHODS: The study included a total of sixty patients newly diagnosed with T2DM. Their fasting blood samples were collected to estimate the glucose, insulin, and leptin levels. IR was calculated using HOMA-IR formula. Statistical analysis was done by Pearson's correlation, Spearman's correlation, and One-sample Wilcoxon Signed Rank test. RESULTS: Leptin and HOMA-IR levels were significantly high in T2DM patients (P < 0.001) when compared with reference values. Body mass index showed a significant positive correlations with insulin (r = 0.40, P < 0.01), HOMA-IR (r = 0.37, P < 0.01), and leptin levels (r = 0.90, P < 0.01). Leptin levels showed significant positive correlations with plasma insulin (r = 0.35, P < 0.01) and HOMA-IR levels (r = 0.31, P < 0.05). The correlation between leptin and HOMA-IR levels was more pronounced and significant among the obese T2DM subjects (r = 0.82, P = 0.01). CONCLUSION: Hyperleptinemia reflecting leptin resistance plays an important role in the development of IR in obeseT2DM patients, making leptin a possible biomarker for the same.