Association between the prognostic nutritional index and 28-day mortality in patients with sepsis-associated liver injury: a retrospective cohort study

Abstract

The mortality rates of patients admitted to intensive care units (ICUs) with sepsis-associated liver injury (SALI) are relatively high; early identification of SALI patients with poor prognosis is necessary. The Prognostic Nutritional Index (PNI) is associated with the mortality rate in conditions such as cancer, cardiovascular disease, and sepsis. However, the correlation between the PNI and mortality rate of patients with SALI remains unclear. Therefore, this study aimed to elucidate the association between the PNI and 28-day mortality in patients with SALI. The admission data of patients diagnosed with SALI admitted to the ICU from 2008 to 2022 were obtained from the Medical Information Mart for Intensive Care-IV database and retrospectively analyzed. The PNI at admission was recorded. Multivariate Cox regression analysis was used to determine the adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). To further validate our findings, we employed a restricted cubic spline (RCS) model, survival curve analysis, receiver operating characteristic (ROC) analysis, and subgroup analysis. This study included 375 patients diagnosed with SALI. The patients were divided into two groups according to the survival status of SALI patients within 28 days: 217 patients were in the survivor group and 158 patients died within 28 days (non-survivor group). Multivariate Cox regression analysis revealed that for every one unit increase in the PNI, the 28-day mortality risk decreased by 7.1%, with an HR of 0.929 (95% CI 0.904–0.955; P<0.001). The RCS model revealed no statistically significant evidence of a non-linear association between PNI and SALI patients’ prognosis. Kaplan–Meier analysis revealed that the group with a lower PNI had a higher 28-day mortality rate. ROC analysis revealed that the optimal cutoff value for the PNI was 32.1. Subgroup analysis showed no significant interaction between the PNI and each subgroup. A lower PNI was significantly associated with an elevated risk of mortality within 28 days in patients with SALI. This finding suggests that PNI may be an independent risk factor for adverse outcomes in patients with SALI. Further studies on the PNI may contribute to advances in the prevention and treatment of SALI.