Exploring the value of blood urea nitrogen to albumin ratio in patients with acute pancreatitis admitted to the intensive care unit: a retrospective cohort study

Jianjun Wang ^1,2 Han Li ³ Pei Yang ¹ Xi Chen ¹ Sirui Chen ¹ Lan Deng ¹ Xintao Zeng ¹ Huiwen Luo ² Dongqing Zhang ⁴ Xianfu Cai ⁵ Hua Luo ^1* Decai Wang ^2*

• ¹ Department of Hepatobiliary Surgery, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang, 621000, China, Mianyang, China
• ² NHC Key Laboratory of Nuclear Technology Medical Transformation, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang, 621000, China, Mianyang, China
• ³ Department of Cardiology, The Fifth Hospital of Wuhan, Wuhan, 430050, China, Wuhan, Hebei Province, China
• ⁴ Department of Rehabilitation Medicine, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang, 621000, China, mianyang, China
• ⁵ Department of Urology, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang, 621000, China, Mianyang, China

Background: Although blood urea nitrogen and albumin alone are well-known clinical indicators, combining them as the blood urea nitrogen to albumin ratio (BAR) may provide additional prognostic information because they reflect the complex interplay between renal function, nutritional status, and systemic inflammation-all of which are key factors in the pathogenesis of acute pancreatitis (AP). Therefore, the objective of this study was to investigate the relationships between BAR and short-and long-term all-cause mortality (ACM) in patients with AP and to assess the prognostic significance of the BAR in AP.Methods: This retrospective investigation utilized information extracted from the Medical Information Mart for Intensive Care-IV database. BAR was calculated using the BUN/ALB ratio obtained from the first measurement within 24 hours of admission. The R software was employed to identify the optimal threshold for the BAR. Kaplan-Meier (K-M) analysis was performed to compare mortality between the two groups. Multivariate Cox proportional hazards regression models and restricted cubic splines (RCS) were used to evaluate the association between BAR and 14-day, 28-day, 90-day, and 1-year ACM. Receiver operating characteristic curves were used to investigate the predictive ability, sensitivity, specificity, and area under the curve (AUC) of the BAR for short-and long-term mortality in AP patients. Subgroup analysis was performed to illustrate the reliability of our findings.This study comprised a total of 569 patients. K-M analysis indicated a notable rise in ACM in patients with higher BAR (all Log-rank P < 0.001). Cox proportional hazards regression models revealed independent associations between higher BAR and ACM before and after adjusting for confounding variables at 14-day, 28-day, 90-day, and 1-year. The RCS analysis revealed J-shaped correlations between the BAR and short-and long-term ACM. The AUC of the BAR for predicting ACM at 14day, 28-day, 90-day, and 1-year were 73.23%, 76.14%, 73.49%, and 71.00%, respectively, which were superior to those of SOFA, and APECHE-II. Subgroup analyses revealed no significant interaction between BAR and the vast majority of subgroups.This study revealed for the first time the unique prognostic value of BAR in ICUmanaged AP patients. Higher levels of BAR were associated with higher short-and long-term ACM in ICU-managed AP patients.