Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by impaired insulin action and increased cardiometabolic risk. Visceral adiposity, insulin resistance, systemic inflammation, and dyslipidemia play key roles in the development of cardiovascular disease in individuals with T2DM. In this context, simple, rapid, and cost-effective biomarkers are increasingly important for risk assessment. The triglyceride-glucose (TyG) index is a practical indicator of insulin resistance, while the Atherogenic Plasma Index (API) reflects cardiovascular risk related to dyslipidemia. The Systemic Immune Inflammation Index (SII), derived from routine blood counts, serves as a marker of systemic inflammation. This study aims to evaluate the predictive value of TyG, API, and SII in assessing insulin resistance, cardiometabolic risk, and inflammation in patients with T2DM, thereby supporting early diagnosis and improved clinical management.

Diabetes mellitus (DM) is a chronic metabolic disorder characterized by the inability to adequately utilize essential nutrients, including carbohydrates, fats, and proteins, as a result of insulin deficiency and/or impaired insulin action. In individuals with type 2 diabetes mellitus (T2DM), comprehensive assessment of cardiovascular disease risk factors and visceral adiposity is of critical importance. Excess visceral fat is closely associated with increased insulin resistance and an elevated risk of cardiovascular disease, reflecting the well-established relationship between cardiometabolic disorders and adiposity. Moreover, excessive body fat accumulation contributes to a chronic low-grade systemic inflammatory state, which plays a central role in the pathogenesis of metabolic syndrome. When metabolic syndrome coexists with dyslipidemia, the risk of cardiovascular disease is further amplified.

In this context, the availability of biomarkers that are easy to apply, rapidly measurable, and cost-effective is of considerable clinical relevance. The triglyceride-glucose (TyG) index has emerged as a practical and reliable parameter for the assessment of insulin resistance. This index is calculated using fasting plasma triglyceride and glucose concentrations, which are routinely measured and widely accessible laboratory parameters. The TyG index provides valuable insight into metabolic disturbances related to insulin resistance and its potential association with cardiovascular disease. The Systemic Immune Inflammation Index (SII) is another emerging biomarker derived from peripheral blood cell counts, calculated using lymphocyte (L), platelet (P), and neutrophil (N) values, and reflects the balance between inflammatory and immune responses. In addition, the Atherogenic Plasma Index (API) serves as an indicator of atherogenic dyslipidemia and may offer information regarding the severity of insulin resistance associated with impaired glucose metabolism, as well as its relationship with cardiovascular risk.

The aim of this study is to evaluate the TyG index as a predictor of insulin resistance, the API as a marker of cardiovascular risk, and the SII as a significant indicator of systemic inflammation in patients diagnosed with T2DM. These novel biochemical indices may facilitate early risk stratification, improve treatment planning, and ultimately contribute to more effective clinical management of individuals with T2DM.

Inclusion Criteria:

• Having a diagnosis of T2DM
• Having a diagnosis of prediabetes
• Being between 18 and 65 years of age.

Exclusion Criteria:

• Having any other chronic disease accompanying T2DM/prediabetes
• Receiving hormone therapy
• Using lipid-lowering agents
• Being pregnant/breastfeeding
• Having an acute infection
• Having any malignant/inflammatory disease

Adult patients with a confirmed diagnosis of type 2 diabetes mellitus or prediabetes attending the Department of Internal Medicine at Tokat Gaziosmanpaşa University Hospital during the study period will constitute the study population. Enrollment will be limited to individuals who meet the eligibility criteria and provide written informed consent.