Systemic Immune-Inflammation Index as a Distinguishing Marker Between Non-Morbid and Morbid Obesity: A Cross- Sectional Evaluation of Derived Inflammatory and Metabolic Indices
Abstract
Morbid obesity is associated with greater metabolic and inflammatory burden than non-morbid obesity; however, the discriminatory ability of hemogram-derived indices between obesity severity groups remains uncertain. This study aimed to compare anthropometric, hematological-biochemical, and derived inflammatory-metabolic indices (SII, NLR, TyG, TG/HDL, ALT/AST) between non-morbid and morbidly obese individuals and to explore their diagnostic value. This retrospective cross-sectional study included 131 obese adults (89 non-morbid, 42 morbid) from an internal medicine outpatient clinic. Anthropometric measurements, complete blood count, biochemical parameters, and derived indices were compared. Data verification, Spearman correlation, ROC curve analysis, and age- and sex-adjusted logistic regression were performed. Analyses remained exploratory because no a priori power analysis was available.
The study included 112 women and 19 men, with no significant difference in sex distribution between groups (p = 0.562). Anthropometric parameters were significantly higher in the morbidly obese group (p <0.001). WBC values were also higher in the morbidly obese group when reported as median (IQR) [7.83 (6.79-9.43) vs. 6.88 (5.77-7.57) ×10^3/μL; p <0.001]. Among derived indices, only SII differed significantly (721.38 vs. 501.40; p = 0.019). SII remained associated with morbid obesity after adjustment for age and sex (OR per 100-unit increase = 1.20; 95% CI: 1.06-1.36; p = 0.005), but its discriminatory performance was weak (AUC = 0.63). BMI was not significantly correlated with SII (rho = 0.100; p = 0.255). Morbid obesity was associated with higher WBC, HbA1c, and SII values in this exploratory cross-sectional sample. SII remained significant after age and sex adjustment, but showed only weak discrimination and was not significantly correlated with BMI. These findings should be interpreted cautiously and require confirmation in larger, adequately powered studies with broader confounder control.
Keywords
Morbid obesity, systemic immune-inflammation index, neutrophil-to-lymphocyte ratio, triglyceride-glucose index, anthropometric measurements, chronic inflammation.
Ethical Statement
Thanks
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