Systemic Inflammation Response Index and Immune-Inflammation Index as Predictors of Metabolic Syndrome in Obese Children and Adolescents: A Prospective Cross-Sectional Study

Background: With the increase in pediatric obesity, the prevalence of metabolic syndrome (MetS) is rising worldwide. Early identification of children with obesity who are prone to developing MetS is important. Objectives: This study aimed to evaluate the value of the Systemic Immune–Inflammation Index (SII) and the Systemic Inflammatory Response Index (SIRI) in predicting MetS in obese children and adolescents. Methods: This prospective single-center cross-sectional study involved 99 children and adolescents with obesity. The patients were assigned to two groups, MetS+ (n = 42) and MetS- (n = 57), based on the presence of MetS. Complete blood count results from the first visit were evaluated. Results: The white blood cell (WBC), platelet, and neutrophil counts were higher in the MetS+ group (P = 0.003, P = 0.022, and P < 0.001, respectively), while no significant difference was observed in lymphocyte (P = 0.865) and monocyte counts (P = 0.488) between the two groups. When inflammatory parameters were compared, SII (P < 0.001), platelet-to-lymphocyte ratio (PLR) (P = 0.024), neutrophil-to-lymphocyte ratio (NLR) (P = 0.002), and SIRI (P = 0.012) were significantly elevated in the MetS+ group compared to the MetS- group. Binary logistic regression analysis revealed that SII and homeostasis model assessment of insulin resistance (HOMA-IR) were statistically significant risk factors for the presence of MetS (P = 0.003, P = 0.012, respectively). Additionally, a significant positive correlation was found between SII and diastolic blood pressure (DBP) (P = 0.024), high-density lipoprotein cholesterol (HDL-C) (P = 0.019), and fasting plasma glucose (FPG) (P = 0.048), as well as between SIRI and HDL-C (P = 0.044) and FPG (P < 0.001). Receiver operating characteristic analysis of the SII and SIRI ability to predict MetS in adolescents and children with obesity showed that the SII was more discriminative than the SIRI, with a specificity of 0.82, sensitivity of 0.57, and an area under the curve of 0.708. Conclusions: The SII and SIRI can be used for the early diagnosis of MetS in pediatric obesity patients.