Association between pan-immune-inflammation and in-hospital mortality in critically ill patients with acute pancreatitis: a cohort study from the MIMIC-IV database

The pan-immune-inflammation value (PIV) is a novel, readily available biomarker that integrates neutrophil, monocyte, lymphocyte, and platelet counts. This study aimed to evaluate the association between the PIV and in-hospital mortality in critically ill patients with acute pancreatitis. This retrospective cohort study used information from the Medical Information Mart for Intensive Care-IV (MIMIC-IV version 3.1) database. Of 7510 patients screened, 277 fulfilled the inclusion criteria (mean [± SD] age 57.0 ± 17.7 years; 56.3% male). In-hospital and 90-day mortality were 18.4% and 24.9%, respectively. When analyzed as a continuous variable, each per-doubling (1-unit increase) of PIV corresponded to a 21% increase in the odds of in-hospital death across all models (fully adjusted OR 1.21 [95% CI 1.04–1.40]; P = 0.015);When analyzed as a categorical variable, patients in the highest tertile (T3) exhibited a significantly higher risk for in-hospital mortality compared with those in the lowest tertile (T1) (OR = 3.56 [95% CI 1.40–9.05], P = 0.008); the association with 90-day mortality lost significance after full adjustment. RCS revealed a linear relationship between log2-PIV and in-hospital mortality (P for nonlinearity = 0.868). Subgroup analyses revealed no significant interactions(all P > 0.05).Our findings indicate that an elevated PIV is an independent predictor of in-hospital mortality in critically ill patients with AP and may serve as a simple and reliable biomarker for early risk stratification and therapeutic guidance. Larger prospective multicenter studies are needed to validate these findings and explore interventions targeting PIV to improve outcomes.