Diagnostic and prognostic value of inflammatory indices in patients with prediabetes and type 2 diabetes mellitus

Background. Type 2 diabetes mellitus (T2DM) is cha­racterized by chronic low-grade inflammation, which significantly contributes to the development of insulin resistance and progressive metabolic dysfunction. Inflammatory indices derived from complete blood count parameters may serve as accessible and cost-effective tools for assessing meta-inflammation. Objective: to determine the levels of systemic immune-inflammation index (SII) and systemic immune-inflammation response index (SIRI) in patients with prediabetes and T2DM in order to assess their diagnostic and prognostic value. Materials and methods. This study included 60 participants divided into three groups: type 2 diabetes, prediabetes, and a control group. The levels of SII, SIRI, HbA1c, arginase, inducible nitric oxide synthase, and other meta­bolic markers were measured. Statistical methods included Kruskal-Wallis test, receiver operating characteristic (ROC) analysis, principal component analysis (PCA), and Spearman correlation. Results. SII was significantly elevated in the T2DM group compared to both the control (p = 0.008) and the prediabetes group (p = 0.2414), indicating the progression of systemic inflammation alongside glycemic dysregulation. Although SIRI did not demonstrate significant between-group differences, it showed a strong correlation with SII in the T2DM group (R = 0.72; p < 0.001). SII is important in the PCA alongside HbA1c and arginase, and ROC analysis for SII revealed its moderate ability to distinguish between diabetic and healthy individuals (AUC = 0.719). Conclusions. SII may be considered a promising and accessible biomarker for early diagnosis and assessment of inflammation in patients with impaired glucose metabolism. ROC analysis data demonstrated moderate diagnostic ability of SII in distinguishing people with T2DM from healthy individuals, which opens opportunities for its use in screening programs, especially at the primary health care level. Inflammatory indices (especially SII) are promising as additional, non-invasive markers for early diagnosis, prognosis and monitoring of therapy effectiveness in patients with carbohydrate metabolism disorders. Their widespread implementation may contribute to personalization of treatment approaches and reduce the risk of cardiovascular complications. Additional studies are needed to develop optimal threshold values of indices that will allow them to be included in standard algorithms for examining patients with impaired carbohydrate metabolism.