Medicine (Baltimore). 2026 Jul 3;105(27):e49667. doi: 10.1097/MD.0000000000049667.
ABSTRACT
BACKGROUND: Metabolic syndrome (MetS) is a cluster of cardiometabolic risk factors that increases the likelihood of cardiovascular disease and type 2 diabetes mellitus. Given the increasing prevalence of MetS, early detection and risk assessment are crucial for mitigating long-term complications. The Systemic Immune-Inflammation Index (SII) has emerged as a potential biomarker for inflammatory conditions; however, its role in MetS remains unclear. This systematic review and meta-analysis aimed to evaluate the association between the SII and MetS.
METHODS: A comprehensive search was conducted across PubMed, Scopus, Embase, and Web of Science databases until June 1, 2026. Eligible studies that assessed the relationship between SII and MetS were included. Data extraction was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, and study quality was assessed using the Joanna Briggs Institute Critical Appraisal Checklist.
RESULTS: The meta-analysis revealed that individuals with MetS had significantly higher SII values as a continuous variable than non-MetS individuals (SMD, 0.34; 95% CI: 0.05-0.64; P = .01). As a categorical variable, an elevated SII was associated with increased odds of MetS (odds ratio = 1.34, 95% CI: 1.08-1.67, P < .01). The diagnostic accuracy of SII showed a pooled area under the receiver operating characteristic curve of 0.69 (95% CI: 0.41-0.98). The pooled sensitivity of the SII for identifying MetS was 0.69 (95% CI: 0.41-0.96), while the pooled specificity was 0.60 (95% CI: 0.55-0.65).
CONCLUSION: The SII score was significantly associated with MetS. However, its diagnostic accuracy was limited (pooled area under the receiver operating characteristic curve = 0.69, based on only 2 studies). The SII may serve as a supplementary marker or risk stratification tool, but more studies are needed to obtain a precise estimate of its diagnostic performance. The observed heterogeneity and very low Grading of Recommendations Assessment, Development and Evaluation evidence further underscore the need for future prospective research to establish standardized cutoff values and clarify its clinical role.
PMID:42410855 | DOI:10.1097/MD.0000000000049667