The systemic immune-inflammation index (SII) as a predictor of acute kidney injury and in-hospital mortality in patients with sepsis and septic shock

Abstract Purpose Sepsis is an infection-induced disorder triggering a life-threatening response in the host. Acute kidney injury (AKI) is a prevalent and serious consequence in septic patients with high rates of morbidity and mortality. The systemic immune-inflammation index (SII) has emerged as a prognostic biomarker in various conditions, but its role in predicting AKI remains unexamined. This study sought to assess the efficacy of SII in predicting AKI and in-hospital mortality in septic patients.. Methods The study involved 120 patients diagnosed with sepsis and septic shock, registered at the Critical Care Medicine Department at Cairo University from November 2023 to July 2024. Sepsis diagnosis was determined according to the third consensus definition of sepsis (Sepsis-3). Upon admission, patients were evaluated through a full medical history, physical examination, and laboratory tests including complete blood count for SII calculation, blood urea nitrogen, and serum creatinine at the time of admission and after 48 h. Results The mean age of the enrolled patients in the study was 66.75 ± 14.84 years. AKI occurred in 42.5% of patients, and the mortality rate was 33.3%. The mean SII value was 2017.38. SII significantly predicted the development of AKI, establishing a cutoff value of > 1602, sensitivity of 84.3%, and specificity of 89.9%. Additionally, SII significantly predicted in-hospital mortality, with a cutoff value of > 1801.411, sensitivity of 95%, and specificity of 90%. Conclusion SII is a potentially valuable, cost-effective, and readily available biomarker that can significantly predict the occurrence of AKI and in-hospital mortality in septic patients.