Association of Serum Ferritin Levels with Short-Term Mortality Risk in Sepsis-associated Acute Kidney Injury: A Retrospective Cohort Study.

Abstract： Background: This study aimed to assess the prognostic significance of serum ferritin levels in sepsis-associated acute kidney injury (SA-AKI) and their correlation with short-term mortality. Despite the established predictive value of serum ferritin in various serious diseases, its specific prognostic relevance in SA-AKI remains unexplored. Therefore, this study aimed to fill this research gap by investigating the association between serum ferritin levels and short-term mortality in patients diagnosed with SA-AKI.

Methods: This retrospective cohort study used clinical information from the Medical Information Mart for Intensive Care-IV(MIMIC-IV) database to include all patients with SA-AKI admitted to the Intensive Care Unit(ICU) for the first time. The relationship between serum ferritin levels and 28-day mortality was explored using restricted cubic splines. Kaplan Meier curves and Cox regression models were utilized to evaluate the association between serum ferritin levels and mortality. Subgroup analysis is used to verify the stability of previous results.

Results: In this study, a total of 878 patients (486 males and 392 females) with a median age of 63.7 years were enrolled. The results showed that increasing serum ferritin levels were linearly associated with a gradual increase in 28-day mortality rates. Specifically, the highest quartile group had a significantly higher 28-day mortality compared to the reference group (the first ferritin quartile). After adjusting for various factors, the fully adjusted hazard ratios (HRs) were calculated to be 1.92 (95% CI: 1.25~2.97, p=0.003).

Conclusion: In patients with SA-AKI, higher serum ferritin levels are associated with an increased 28-day mortality rate.