Association between the blood urea nitrogen to serum albumin ratio and the risk of mortality in patients with chronic kidney disease: a cohort study

Abstract Background Chronic kidney disease (CKD) is prevalent worldwide, with patients facing significant mortality risk in intensive care units (ICUs). Early identification of high-risk CKD patients is crucial for improving clinical outcomes. The blood urea nitrogen to albumin ratio (BAR) is a simp...

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Main Authors: Kaiying He, Yan Zhu, Wansong Wang, Zhihui Wang, Shiwan Guo, Jing Wu
Format: Article
Language:English
Published: BMC 2025-06-01
Series:BMC Nephrology
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Online Access:https://doi.org/10.1186/s12882-025-04214-z
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author Kaiying He
Yan Zhu
Wansong Wang
Zhihui Wang
Shiwan Guo
Jing Wu
author_facet Kaiying He
Yan Zhu
Wansong Wang
Zhihui Wang
Shiwan Guo
Jing Wu
author_sort Kaiying He
collection DOAJ
description Abstract Background Chronic kidney disease (CKD) is prevalent worldwide, with patients facing significant mortality risk in intensive care units (ICUs). Early identification of high-risk CKD patients is crucial for improving clinical outcomes. The blood urea nitrogen to albumin ratio (BAR) is a simple and measurable indicator, but its relationship with 28-day mortality in CKD patients is not well established. This study aimed to investigate this association. Methods We conducted a retrospective analysis of eligible CKD patients from the MIMIC IV database. The association between the BAR and 28-day mortality was assessed using Kaplan-Meier survival curves, multivariable Cox regression models, and restricted cubic spline models. Results A total of 4,625 patients were included, with a 28-day mortality rate of 25.2%. Kaplan-Meier survival curve analysis indicated that patients in the high BAR tertile had significantly lower survival probabilities than those in the low BAR tertile. The adjusted Cox regression model showed that compared to low BAR patients (T1 ≤ 9.8 mg/g), those in T2 (10.0-17.4 mg/g) and T3 (≥ 17.5 mg/g) had increased risks of 28-day mortality, with HRs of 1.49 (95% CI: 1.26–1.76) and 2.04 (95% CI: 1.73–2.40), respectively. Restricted cubic spline analysis indicated a nonlinear association. Conclusion The BAR is significantly associated with 28-day mortality risk in ICU patients with CKD and may serve as a valuable tool for mortality risk stratification.
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spelling doaj-art-0eb7585983f44bd482e49fd0ca8b19bb2025-08-20T03:25:12ZengBMCBMC Nephrology1471-23692025-06-0126111010.1186/s12882-025-04214-zAssociation between the blood urea nitrogen to serum albumin ratio and the risk of mortality in patients with chronic kidney disease: a cohort studyKaiying He0Yan Zhu1Wansong Wang2Zhihui Wang3Shiwan Guo4Jing Wu5Department of Nephrology, The Affiliated People’s Hospital of Fujian University of Traditional Chinese MedicineNanchang Institute of TechnologyDepartment of Rehabilitation Medicine, The First Affiliated Hospital, Jiangxi Medical College, Nanchang UniversityDepartment of Nephrology, The Affiliated People’s Hospital of Fujian University of Traditional Chinese MedicineDepartment of Traditional Chinese Medicine, Ganzhou People’s HospitalDepartment of Nephrology, The Affiliated People’s Hospital of Fujian University of Traditional Chinese MedicineAbstract Background Chronic kidney disease (CKD) is prevalent worldwide, with patients facing significant mortality risk in intensive care units (ICUs). Early identification of high-risk CKD patients is crucial for improving clinical outcomes. The blood urea nitrogen to albumin ratio (BAR) is a simple and measurable indicator, but its relationship with 28-day mortality in CKD patients is not well established. This study aimed to investigate this association. Methods We conducted a retrospective analysis of eligible CKD patients from the MIMIC IV database. The association between the BAR and 28-day mortality was assessed using Kaplan-Meier survival curves, multivariable Cox regression models, and restricted cubic spline models. Results A total of 4,625 patients were included, with a 28-day mortality rate of 25.2%. Kaplan-Meier survival curve analysis indicated that patients in the high BAR tertile had significantly lower survival probabilities than those in the low BAR tertile. The adjusted Cox regression model showed that compared to low BAR patients (T1 ≤ 9.8 mg/g), those in T2 (10.0-17.4 mg/g) and T3 (≥ 17.5 mg/g) had increased risks of 28-day mortality, with HRs of 1.49 (95% CI: 1.26–1.76) and 2.04 (95% CI: 1.73–2.40), respectively. Restricted cubic spline analysis indicated a nonlinear association. Conclusion The BAR is significantly associated with 28-day mortality risk in ICU patients with CKD and may serve as a valuable tool for mortality risk stratification.https://doi.org/10.1186/s12882-025-04214-zBARCKDMortalityBlood urea nitrogenSerum albuminMIMIC-IV database
spellingShingle Kaiying He
Yan Zhu
Wansong Wang
Zhihui Wang
Shiwan Guo
Jing Wu
Association between the blood urea nitrogen to serum albumin ratio and the risk of mortality in patients with chronic kidney disease: a cohort study
BMC Nephrology
BAR
CKD
Mortality
Blood urea nitrogen
Serum albumin
MIMIC-IV database
title Association between the blood urea nitrogen to serum albumin ratio and the risk of mortality in patients with chronic kidney disease: a cohort study
title_full Association between the blood urea nitrogen to serum albumin ratio and the risk of mortality in patients with chronic kidney disease: a cohort study
title_fullStr Association between the blood urea nitrogen to serum albumin ratio and the risk of mortality in patients with chronic kidney disease: a cohort study
title_full_unstemmed Association between the blood urea nitrogen to serum albumin ratio and the risk of mortality in patients with chronic kidney disease: a cohort study
title_short Association between the blood urea nitrogen to serum albumin ratio and the risk of mortality in patients with chronic kidney disease: a cohort study
title_sort association between the blood urea nitrogen to serum albumin ratio and the risk of mortality in patients with chronic kidney disease a cohort study
topic BAR
CKD
Mortality
Blood urea nitrogen
Serum albumin
MIMIC-IV database
url https://doi.org/10.1186/s12882-025-04214-z
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