Association between systemic immune-inflammation index and mortality in patients admitted to the intensive care unit...

Major abdominal surgery is associated with a high incidence of postoperative complications, morbidity, and mortality. The Systemic Immune-Inflammation Index (SII), calculated from neutrophil, platelet, and lymphocyte counts, reflects both inflammatory and immune status and has been shown to predict outcomes in various diseases. This study aimed to retrospectively evaluate the outcomes of patients admitted to the intensive care unit (ICU) after urgent or elective major abdominal surgery and to investigate the association between postoperative SII and ICU mortality.

We retrospectively analyzed patients admitted to the surgical ICU after major abdominal surgery between November 2022 and November 2023. Patients who died within the first 24 hours of ICU admission, were admitted to the ICU for less than 48 hours, and were younger than 18 years were excluded.

During the study period, 360 patients were admitted to the surgical ICU, of whom 102 underwent major abdominal surgery. One patient was excluded because of death within the first 24 hours of ICU admission, leaving 101 patients for analysis. Fifty-nine patients (58.4%) were women, and the mean age was 70.1±15.2 years. Urgent abdominal surgery was performed in 42 patients (41.6%). ICU mortality was higher among patients who underwent urgent surgery (23.8%) than among those who underwent elective surgery (5.1%) (p=0.013). Receiver operating characteristic (ROC) curve analysis identified a postoperative SII cutoff value of 998.26. A low postoperative SII was independently associated with mortality after major abdominal surgery, with a sensitivity of 82.9% and a specificity of 69.2% (95% confidence interval: 0.0579-0.913, p=0.004).

Postoperative SII may be a useful prognostic marker for predicting clinical outcomes and mortality in patients undergoing major abdominal surgery.