Association between admission systemic immune-inflammation index and mortality in critically ill patients with sepsis: a retrospective cohort study based on MIMIC-IV database

Abstract

Systemic immune-inflammation index (SII) has been identified as a prognostic biomarker for various diseases. Our study aimed to investigate the association between SII and mortality risk in critically ill patients with sepsis, thus exploring possible tools for rapid screening. This retrospective cohort study was conducted using clinical data extracted from the Medical Information Mart for Intensive Care Database. The study included only patients diagnosed with sepsis admitted to the intensive care unit for the first time. We used the restricted cubic splines to explore the relationship between SII and 28-day mortality. Kaplan-Meier curve and Cox regression models were performed to evaluate the association between SII and mortality. Subgroup analysis was performed to explore the stability of the primary results. A total of 16,007 patients with sepsis were eligible in the final analysis. We found a J-shaped relationship between SII and mortality risk. The SII level associated with the lowest mortality risk was 774.46*10 9 /L. Compared with the reference group (second SII quartile), the 28-day mortality was increased in the highest quartile and third quartile groups of SII levels; fully adjusted HRs were 1.16 (1.02 to 1.32) and 1.40 (1.23 to 1.58), respectively. However, although the lower SII (Q1 group) also showed a trend toward a higher hazard of 28-day mortality, there was no statistical difference, with a fully adjusted HR of 1.05 (0.92 to 1.21). In the population of critically ill patients with sepsis, low and high SII levels were associated with an increased risk of short-term mortality. The 28-day mortality risk was lowest at SII levels of 774.46*10 9 /L.

Systemic Immune-Inflammation Index (SII) as a Predictor of Short-Term Mortality Risk in Sepsis-Associated Acute Kidney Injury: A Retrospective Cohort Study

“…Our study found that the higher SII groups (Q3 and Q4) had higher 28-day mortality in patients with SA-AKI. The 28-day mortality rate in the low SII group (Q1) was higher compared to the Q2 group, but the difference was not significant, consistent with previous findings in critically ill patients [24]. The literature contains little information on the relationship between the SII and short-term mortality in SA-AKI [25].…”

Unraveling the clinical significance and prognostic value of the neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, systemic immune-inflammation index, systemic inflammation response index, and delta neutrophil index

“…In this study, the lowest risk of 28-day mortality was at the SII levels of 774.46 × 10 9 /L. [ 112 ]…”

Association between preoperative systemic immune inflammation index and postoperative sepsis in patients with intestinal obstruction: A retrospective observational cohort study

“… 21 , 33 However, a retrospective study showed that not only is a higher SII associated with the death of critically ill patients with sepsis, but a lower SII also led to an increased risk of short‐term death. 22 Low SII levels theoretically signal that the body may be suffering from significant inflammation and immune suppression disorder. However, intestinal obstruction patients who are about to undergo surgical treatment rarely experience these conditions before surgery.…”

“… 21 Meanwhile, a retrospective study showed that SII was associated with short‐term mortality in the population of critically ill patients with sepsis. 22 However, there have been limited studies on the inflammatory factors in patients with intestinal obstruction who are at a high risk of developing postoperative sepsis. We speculated that SII is a risk factor for sepsis after intestinal obstruction surgery.…”