Systemic Inflammation Response Index (SIRI) independently predicts ICU requirement in vancomycin-treated adults

Vancomycin (VAN) serves as the primary treatment for severe Gram-positive bacterial infections, including those caused by methicillin-resistant Staphylococcus aureus (MRSA). Despite its efficacy, managing patients on VAN therapy, particularly those at risk of severe outcomes like intensive care unit (ICU) admission, remains challenging. Identifying reliable, cost-effective biomarkers for early risk stratification is crucial to optimize patient management and improve clinical outcomes. The systemic inflammation response index (SIRI), derived from routine blood counts, has shown promise in various inflammatory and infectious conditions, but its specific utility and determinants during VAN therapy have not been thoroughly investigated. This gap highlights the need for a comprehensive understanding of SIRI's role in this specific patient population.

This retrospective cross-sectional study analyzed the medical records of 299 adult patients who consecutively received vancomycin therapy. The research aimed to identify clinical and biochemical determinants of the systemic inflammation response index (SIRI) within this cohort. Data collection involved extracting demographic, clinical, and laboratory parameters. Statistical analyses included calculating prevalence rates, employing Spearman's correlation to assess associations between SIRI and various variables, and utilizing regression models to identify independent predictors. Risk assessment was performed using prevalence ratios and odds ratios, while the diagnostic potential of SIRI was evaluated through receiver operating characteristic (ROC) curves.

The systemic inflammation response index (SIRI) was significantly elevated in patients requiring intensive care unit (ICU) admission compared to non-ICU patients receiving vancomycin therapy, demonstrating a highly significant difference (p < 0.0001). A comprehensive analysis revealed that age, blood pressure, creatinine, Na+, CO2, albumin, aspartate transaminase (AST), gamma-glutamyl transferase (GGT), bilirubin, the coefficient of variation in red cell distribution width (RDW-CV), and platelet count all exhibited significant and differential correlations with SIRI levels. > In the adjusted multivariate analysis, ICU requirement emerged as the strongest independent predictor of SIRI, with ICU patients displaying a 2.13-fold higher SIRI compared to their non-ICU counterparts (p < 0.0001). Furthermore, the prevalence of ICU requirement was 1.61 times higher in individuals presenting with an increased SIRI (p = 0.0018), and their odds of requiring ICU admission were 2.16 times greater (p = 0.0016). The SIRI also demonstrated moderate discriminatory ability for predicting ICU admission, with its highest performance observed in patients younger than 50 years (area under the curve [AUC] = 0.731, p = 0.0001). These findings underscore SIRI's potential as a robust indicator of severe clinical outcomes in this patient group.