Association between pan-immune-inflammation value and metabolic syndrome in US adults: findings from NHANES 2013–2020

The worldwide incidence of Metabolic Syndrome (MetS) is growing sharply, imposing a heavy burden on individual health and healthcare systems. While the pan-immune inflammation value (PIV) is considered an innovative biomarker of immune status and systemic inflammation, evidence evaluating its relationship with MetS remains lacking. This investigation examines the connection between PIV and MetS to provide more targeted clinical recommendations. This investigation comprised 15,846 adults from the 2013–2020 National Health and Nutrition Examination Survey, among whom 3845 were with MetS. Participants were stratified into PIV quartiles, and variations across groups were assessed via the Kruskal–Wallis test and weighted chi-square tests. Weighted multivariable logistic regression analysis, sensitivity and subgroup analyses, and restricted cubic spline (RCS) were utilized to assess the link between PIV and MetS. Our investigation illustrated a positive correlation between PIV and MetS across all four models (Model 1: OR = 1.19, 95% CI: 1.13–1.26, P < 0.001; Model 2: OR = 1.17, 95% CI: 1.10–1.24, P < 0.001; Model 3: OR = 1.19, 95% CI: 1.12–1.27, P < 0.001; Model 4: OR = 1.12, 95% CI: 1.04–1.19, P = 0.002). RCS analysis showed a non-linear link between PIV and MetS ( P = 0.044 for non-linearity). Stratified analysis illustrated a constant positive relationship between PIV and MetS across all subgroups. After excluding participants receiving fibrates/ω-3 or glucose-/blood pressure–lowering medications, the association between PIV and MetS became more robust (OR = 1.73; 95% CI: 1.26–2.38; P < 0.05). Additionally, PIV remained significantly and positively associated with MetS when defined using the Harmonized criteria. Using random forest imputation for missing values, the association remained stable in Models 1–3 but attenuated in Model 4. Our study demonstrated a positive association between higher PIV and the presence of MetS. Further prospective cohort studies in diverse populations are needed to determine whether PIV can serve as a clinical screening tool for metabolic syndrome risk. Not applicable.