Systemic Immune-Inflammation Index in Relation to Diabetes Markers in Saudi Adults: A Retrospective Study

Background and objectives: Low-grade inflammation is associated with metabolic disturbances like diabetes. The systemic immune-inflammation index (SII) has been proposed as a predictive tool to identify individuals at a greater risk of diabetes. This study aims to examine the association between SII and diabetes markers. Method and materials: We used retrospective data from a large cohort of adults (n = 3895) aged ≥18 in Saudi Arabia. The SII was calculated, and the markers of diabetes such as fasting blood glucose (FBG), insulin, and hemoglobin A1c (HbA1c) were included. Results: Across the quartiles of SII, FBG, insulin, and HbA1c were significantly higher in adults with higher compared to lower SII (p < 0.0001, p = 0.04, p < 0.0001, respectively). A two SD higher FBG was significantly associated with an SII difference of 47.7 (95% CI: (15.5, 91.9)). In subgroup analysis, this relationship prevailed in normal-weight participants and among those with normoglycemia and prediabetes but was attenuated in participants with diabetes. The association also prevailed in separate analyses for males and females but was stronger among females. Linear regression models showed no significant association between insulin, HbA1c, and SII. Conclusions: SII was associated with the markers of diabetes. The utility of SII for predicting diabetes can be confirmed with prospective cohort studies.