Prognostic Nutritional Index as a novel biomarker for predicting prognosis in sepsis-associated encephalopathy: A multicenter retrospective cohort study

Background Sepsis-associated encephalopathy (SAE) still has a high mortality rate, and there is a lack of effective biomarkers to assess the prognosis of SAE. This study aims to explore the relationship between prognostic nutritional index (PNI) and the prognosis of patients with SAE. Methods This study is a multicenter cohort study, data from 2008–2019. The primary outcome was 28-day all-cause mortality in the SAE population. To explore the prognostic relationship between PNI and SAE patients, the multivariable Logistic regression, propensity score matching, inverse probability weighting were conducted to adjust confounders. In this study, the generalized additive model (GAM), Kaplan-Meier curve, receiver operating characteristic curve (ROC) curve and other methods were used to analyze the relationship between PNI and the 28-day mortality rate of SAE patients. The results of this study were validated by external data. Results Among 3,202 SAE patients, multivariable analysis identified PNI as an independent predictor of 28-day mortality (OR: 0.85, 95% CI: 0.77–0.93) of original cohort. GAM of original cohort showed that a PNI of 34 was the optimal prognostic threshold for SAE patients. The Kaplan-Meier curves of both the original cohort and the external validation cohort showed that the 28-day mortality rate of SAE patients with PNI lower than 34 was significantly lower than that of patients with PIN higher than 34 ( P  < 0.001). ROC analysis showed superior predictive performance in original cohort (AUC: 0.879; sensitivity: 0.878; specificity: 0.880) versus external validation cohort (AUC: 0.724; sensitivity: 0.878; specificity: 0.569). Stratified analysis of the results of the study showed that elevated PNI correlated with higher Glasgow Coma Scale scores ( P  < 0.001). Conclusions This large-scale multicenter study establishes the PNI as an independent predictor of 28-day mortality in patients with sepsis-associated encephalopathy (SAE). We identified that SAE patients with PNI < 34 exhibited significantly higher 28-day mortality rates and worse neurological function.