This prospective observational study aims to evaluate serum Neuregulin-4 (NRG4) concentrations in obese and non-obese adults with Type 2 Diabetes Mellitus (T2DM) and to investigate their association with obesity status, insulin resistance, and different antidiabetic treatment regimens. Participants will be categorized into five predefined groups according to obesity status and treatment regimen, including SGLT2 inhibitor users, non-SGLT2 oral antidiabetic therapy users, SGLT2 combination therapy users, newly diagnosed treatment-naïve patients, and healthy controls. Clinical, anthropometric, and laboratory parameters including fasting plasma glucose, HbA1c, estimated glomerular filtration rate (eGFR), body mass index, waist circumference, waist-to-hip ratio, and serum NRG4 concentrations will be evaluated. The study aims to determine whether NRG4 may serve as a novel biomarker reflecting metabolic status and treatment response in patients with T2DM.