The systemic immune-inflammation index is associated with Type 2 diabetes mellitus patients: Evidence from NHANES 2011-2018

Backgrounds The Systemic Immune-Inflammation Index (SII), as a novel inflammatory biomarker, has not been researched for type 2 diabetes mellitus (T2DM). This study was designed to investigate the potential association between SII and T2DM. Methods This cross-sectional study focused on adults enrolled in 2011 and 2018 by National Health and Nutrition Examination Survey (NHANES). Univariate, as well as multivariate logistic regression analyses, subgroup analyses, and sensitivity analyses, were performed to determine the independent association between SII and T2DM. The relationship between ln-SII and T2DM was described by the fitted smoothing curve. Results A total of 10,321 subjects were enrolled in the study; of which 2,078 (20.1%) were diagnosed with T2DM. After full adjustment, multivariate logistic regression demonstrated that higher SII was an independent risk factor for increased T2DM (OR = 1.30; 95% CI, 1.08–1.56, p < 0.0001). There was no relevant association of age, race, physical activity, high blood pressure, and smoking status(all p < 0.05), as demonstrated by the subgroup analysis and the interaction study. In addition, the relationship between SII and T2DM is non-linear; as ln-SII increases, the potential for T2DM gradually increases. Conclusions Elevated SII levels were linked to a higher probability of developing T2DM. More large and prospective studies will be required to confirm the results of this study.