Blood Urea Nitrogen to Albumin Ratio Was Associated With Mortality in Critically Ill Septic Patients: A Multicenter Retrospective Propensity–Adjusted Analysis

Abstract

Background: Sepsis is a leading cause of mortality worldwide, and increasing studies have found that high ratio of blood urea nitrogen to blood albumin ratio (BAR) was associated with mortality in inflammatory diseases. We used a multicenter database and propensity score–adjusted approach to address the mortality association of BAR in critically ill septic patients.

Methods: Using the eICU Collaborative Research Database, we enrolled adult septic patients who fulfilled the sepsis-3 criteria. We used Cox proportional hazards analysis and propensity score–adjusted analyses, consisting of propensity score matching (PSM), inverse probability of treatment weighting (IPTW), and covariate balancing propensity score (CBPS) to determine hazard ratios (HRs) and 95% confidence intervals (CIs) of in-hospital all-cause mortality.

Results: We analyzed data from 8069 critically ill septic patients in 335 ICUs. The median age was 67 (interquartile range, 56–79) years, with 46.9% being female. The nonsurvivors (31.4%) were older and had higher APACHE IV scores, more shock, and more mechanical ventilation usage. Cox regression identified that higher BAR was independently associated with increased mortality (adjusted HR 1.247, 95% CI 1.142–1.361) after adjusting for covariates. The propensity score–based approach found a consistent and robust association, with adjHRs in the PSM, IPTW, and CBPS populations were 1.191 (95% CI 1.074–1.321), 1.178 (95% CI 1.068–1.299), and 1.215 (95% CI 1.111–1.329), respectively.

Conclusions: This multicenter study demonstrated that high BAR, which is a ready-for-use biomarker in critical care, correlated with increased mortality in critically ill septic patients, and more studies are warranted to explore the underlying mechanism.