Prognostic Nutritional Index as a Predictor of Mortality in Intensive Care Unit Patients with Pressure Injuries: Insights from a Large Cohort Study

Abstract

Objective:

To investigate the association between the Prognostic Nutritional Index (PNI) and mortality risk in intensive care unit (ICU) patients with pressure injuries (PIs) to provide a basis for early risk stratification and clinical decision-making.

Approach:

This retrospective cohort study used data from the Medical Information Mart for Intensive Care IV database, which included 972 ICU patients diagnosed with PI. Patients were stratified by median PNI levels, and Kaplan–Meier survival analysis, Cox regression, logistic regression, restricted cubic splines, and propensity score matching (PSM) were performed to assess the relationship between PNI and 28-day, 90-day, and ICU mortality.

Results:

A higher PNI was significantly associated with lower 28-day (hazard ratio [HR] = 0.702, 95% confidence interval [CI] 0.551–0.895), 90-day (HR = 0.722, 95% CI: 0.576–0.905), and ICU mortality (odds ratio [OR] = 0.644, 95% CI: 0.474–0.872). An L-shaped relationship between the PNI and all-cause mortality was observed. This association remained robust after multivariate adjustment, subgroup analysis, and PSM.

Innovation:

This study is the first to evaluate the prognostic significance of the PNI in ICU patients with PIs, addressing the gap in current research by identifying a simple and accessible marker associated with mortality risk in this vulnerable population.

Conclusion:

PNI can be calculated from routine laboratory results and may guide early nutritional or wound care interventions in ICU patients with PI. A PNI value below 19.02 is associated with an increased risk of mortality (i.e., PNI <19.02 = high risk) and serves as a critical threshold for identifying patients at elevated risk.