Comparative Analysis of Systemic Immune Inflammation Index and Systemic Inflammation Response Index in Predicting Outcomes of Upper Gastrointestinal Bleeding

Background and objectives: Upper gastrointestinal bleeding (UGIB) is a common cause of emergency department admissions with significant mortality risk. Risk stratification remains challenging in clinical practice. This study aimed to evaluate the associations of inflammatory biomarkers including Neutrophil-to-Lymphocyte Ratio (NLR), Platelet-to-Lymphocyte Ratio (PLR), Monocyte-to-Lymphocyte Ratio (MLR), Systemic Immune Inflammation Index (SII), and Systemic Inflammation Response Index (SIRI) with intensive care admission rates and 30-day mortality in patients with UGIB. Materials and Methods: A retrospective cohort study was conducted, including 307 patients with UGIB treated. Inflammatory biomarkers were calculated from admission hemogram results. The associations of these biomarkers with intensive care admission and 30-day mortality (survivors vs. non-survivors) were analyzed. ROC analysis was performed to evaluate the predictive value of inflammatory parameters for mortality. Results: The 30-day mortality rate was 14.3%. Significant differences were observed between survivors and non-survivors in terms of SII (median 1268vs. 2544, p=0.030) and SIRI values (median 3.96vs. 9.23, p=0.003). Furthermore, SIRI values exhibited substantial variances among the various Forrest bleeding classification groups (p=0.037). ROC analysis revealed that SII (AUC 61.1%, cut-off 1056.8) and SIRI (AUC 67.5%, cut-off 3.19) had limited predictive value for mortality. After adjusting for age, comorbidities, and bleeding etiology in multivariable analysis, SIRI remained independently associated with mortality. Conclusions: SII and SIRI demonstrate statistically significant associations with mortality in UGIB patients, though with limited discriminative ability. These biomarkers, which are easily calculable from routine blood tests, may serve as supplementary tools in the risk assessment of UGIB patients. Further prospective studies with larger cohorts are required to confirm these findings and investigate their potential clinical applications.