Relationship Between Blood Urea Nitrogen to Albumin Ratio and Risks of Mortality and Delirium in Pancreatitis Patients: A Retrospective Analysis of the MIMIC-IV Database

Background and objective: This study is aimed at evaluating the predictive value of the blood urea nitrogen-to-albumin ratio (BAR) for both mortality and delirium risk in patients with pancreatitis. Pancreatitis carries a substantial mortality risk and significant long-term sequelae, with delirium being a severe neurological complication, underscoring the clinical need for effective prognostic markers.

Methods

A retrospective cohort study was performed using the MIMIC-IV v3.0 database. A total of 1748 ICU patients meeting diagnostic criteria for pancreatitis (ICD-9/10 codes: 577.0, 577.1, K85) with documented baseline blood urea nitrogen (BUN) and albumin levels were included. BAR was calculated (BUN[mg/dL]/Albumin[g/dL]) and patients were stratified into quartiles (Q1: BAR < 3.0; Q2: BAR 3.0-5.0; Q3: BAR 5.0-9.2; Q4: BAR ≥ 9.2). The primary endpoints were all-cause mortality and delirium occurrence (identified using ICD-9 codes 293.0, 293.1, and ICD-10 codes F05, F05.9). Multivariable Cox proportional hazards regression (mortality) and logistic regression (delirium) were employed, adjusting for demographics, illness severity scores (GCS, SAPS II, OASIS, and Charlson Comorbidity Index), and comorbidities. Restricted cubic splines (RCS) were used to explore nonlinear associations.