The Association and Prognostic Value of Systemic Inflammatory Response Index with Short and Long-term Mortality in Patients with Sepsis

This study evaluated the association and prognostic significance of the systemic inflammation response index (SIRI) with mortality in sepsis. In this cohort study, the sepsis patients were retrieved from the Medical Information Mart for Intensive Care III (MIMIC-III) and MIMIC-IV intensive care unit (ICU) databases. SIRI was calculated by using the neutrophil, monocyte, and lymphocyte counts. The outcomes were 28-day mortality, 1-year mortality, and 28 days to 1-year mortality. The Cox proportional hazards model with a hazard ratio (HR) and a 95% confidence interval (CI) was used to investigate the association and prognostic value of SIRI with mortality in sepsis. Subgroup analyses of the associations of SIRI with 28-day and 1-year mortality in sepsis were based on age, gender, Simplified Acute Physiology Score II (SAPSII), Sequential Organ Failure Assessment (SOFA), and presence or absence of septic shock. The receiver operating characteristic (ROC) curve was used to compare the predictive performances of SIRI, SOFA and SAPS II for mortality in sepsis. Of the 4239 patients included, 1339 patients suffered from 28-day mortality, 2085 patients suffering from 1-year mortality, and 746 (25.72%) suffered from 28 days to 1-year mortality. High SIRI levels exhibited higher risks of 28-day mortality (HR: 1.15, 95% CI: 1.03-1.29, P = .010), 1-year mortality (HR: 1.14, 95% CI: 1.04-1.24, P = .003), and 28 days to 1-year mortality (HR: 1.16, 95% CI: 1.01-1.35, P = .047) in sepsis. A higher SIRI was reported related to 28-day mortality and 1-year mortality in sepsis patients with female gender, with SOFA < 8, with SAPS II < 44, and in sepsis patients without sepsis shock. The AUC of SIRS, SOFA, and SAPS II in predicting 28-day mortality in sepsis were 0.726, 0.591, and 0.644, respectively. The AUC of SIRI in predicting 1-year mortality in sepsis was 0.761, higher than the AUC values of SOFA and SAPS II. A higher AUC value of SIRI compared with SOFA, and SAPS II in predicting 28 days to 1-year mortality was observed. Elevated SIRI was associated with an increased risk of mortality in sepsis. SIRI is an independent prognostic biomarker of mortality in sepsis.