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High blood urea nitrogen to albumin ratio values in patients with CKD are linked to greater mortality, indicating its potential value as a prognostic indicator.

Higher blood urea nitrogen to albumin ratio (BAR) values in patients with chronic kidney disease (CKD) in the ICU are significantly linked with increased 28-day mortality risk, according to a study published in BMC Nephrology.

“BAR may serve as a valuable and straightforward indicator for mortality risk stratification,” researchers wrote.

Although relatively simple, the BAR has shown predictive utility in various diseases, the study authors continued, including coronary artery disease, sepsis, and intracerebral hemorrhage.

“By combining levels of urea nitrogen and albumin, BAR provides a comprehensive reflection of renal function, protein metabolism, and chronic inflammatory status, potentially offering a more holistic risk assessment for ICU patients with CKD.”

The study investigated the association between BAR and 28-day mortality risk in 4,625 adult patients from the publicly available Medical Information Mart for Intensive Care IV database, which included health records for patients in the ICU at Beth Israel Deaconess Medical Center between 2008 and 2022.

Associations Between BAR & 28-Day Mortality

According to the findings, the 28-day mortality rate in the cohort was 25.2%. By tertile, mortality rates were 14.6% in Tertile 1 (BAR, ≤9.8 mg/g), 24.6% in Tertile 2 (BAR, 10.0-17.4 mg/g), and 36.3% in Tertile 3 (BAR, ≥17.5 mg/g).

The Kaplan-Meier survival curves analysis revealed a notable decline in survival rates for patients in tertiles 2 and 3 compared with those in tertile 1, suggesting a potential link between higher BAR levels and lower survival probabilities.

Adjusted Cox regression analysis confirmed the increased 28-day mortality risk in patients with a higher BAR. Compared with tertile 1, tertile 2 had a 1.49 hazard ratio, and tertile 3 had a 2.04 hazard ratio for 28-day mortality.

Restricted cubic spline analysis demonstrated a nonlinear association between BAR and 28-day mortality rate.

“The mortality risk significantly increased until the BAR value reached the inflection point, after which the risk remained high and stabilized,” the study team wrote.

In a receiver operating characteristic curve analysis of BAR, serum albumin, and blood urea nitrogen for predicting 28-day morality, the area under the curve was highest (0.643) for BAR.

“Therefore, we propose that BAR could serve as an independent and effective clinical indicator for the prognosis of critically ill CKD patients,” the researchers wrote.