Association of the Blood Urea Nitrogen-to-Albumin Ratio with Clinical Outcomes in Patients with Cardiorenal Syndrome Presenting to the Emergency Department: A Retrospective Study

Q: What are the key findings of this study?

Blood urea nitrogen-to-albumin ratio showed modest discrimination for hemodialysis within 48 hours (AUC 0.694, p<0.001) in cardiorenal syndrome, but was not associated with mortality (p=0.207).

Q: What is the clinical evidence from this study?

Study design: Observational. Population: Cardiorenal syndrome (n=201). Intervention: Blood urea nitrogen-to-albumin ratio (BAR) vs. Blood urea nitrogen (BUN) or albumin alone / patients without clinical outcomes. Primary outcome: Hemodialysis requirement within 48 hours (AUC 0.694, 95% CI 0.609-0.779, p=<0.001).

Q: What does this research mean for the field?

In patients with cardiorenal syndrome presenting to the emergency department, an elevated blood urea nitrogen-to-albumin ratio provides modest discrimination for early hemodialysis requirement but is not associated with in-hospital mortality and offers no prognostic superiority over blood urea nitrogen alone. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

Q: What question did this study set out to answer?

To evaluate the association of the blood urea nitrogen-to-albumin ratio with in-hospital mortality, intensive care unit admission, and hemodialysis requirement in emergency department patients with cardiorenal syndrome.

Muhammed Emin Dut; Hüseyin Acar; Osman Sezer Çınaroğlu; Ejder Saylav Bora; Melih Şengül

doi:10.21203/rs.3.rs-11152451/v1

October 14, 2026Open Access

Association of the Blood Urea Nitrogen-to-Albumin Ratio with Clinical Outcomes in Patients with Cardiorenal Syndrome Presenting to the Emergency Department: A Retrospective Study

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Key result

BUN-to-albumin ratio modestly predicts early hemodialysis in cardiorenal syndrome, but not mortality.

AUC 0.694
95% CI 0.609-0.779
P<0.001
n=201

Why the study?

Cardiorenal syndrome carries high morbidity and mortality, and the limitations of existing cardiac and renal biomarkers necessitate readily accessible prognostic indicators such as the blood urea nitrogen-to-albumin ratio.

Does the blood urea nitrogen-to-albumin ratio (BAR) predict in-hospital mortality, ICU admission, and hemodialysis requirement within 48 hours in adults with cardiorenal syndrome presenting to the emergency department?

Key Points

To evaluate the association of the blood urea nitrogen-to-albumin ratio with in-hospital mortality, intensive care unit admission, and hemodialysis requirement in emergency department patients with cardiorenal syndrome.
Single-center retrospective study of 201 adults presenting with cardiorenal syndrome to a tertiary emergency department between May 1, 2023, and April 30, 2025.
Laboratory and clinical markers were evaluated using Welch's t-test or the Mann–Whitney U test, and discrimination for hemodialysis within 48 hours was assessed using receiver operating characteristic (ROC) curves and DeLong's test.
Hemodialysis within 48 hours occurred in 58 patients (28.9%); median ratio was higher in those requiring hemodialysis (2.51 vs. 1.75; p < 0.001), yielding an AUC of 0.694 (95% CI, 0.609–0.779) with 48.3% sensitivity and 88.1% specificity at a cutoff of 2.64.
The ratio's AUC for early hemodialysis did not differ significantly from blood urea nitrogen alone (0.709; p = 0.230), although it was significantly higher than albumin alone (0.476; p < 0.001).
The blood urea nitrogen-to-albumin ratio did not differ significantly by in-hospital mortality (1.96 vs. 1.83; p = 0.207; overall mortality 33.3%) or intensive care unit admission (1.97 vs. 1.81; p = 0.209; overall rate 52.2%).

Study Design

Type

Observational (n=201)

Multicenter

No

Structured PICO

Does the blood urea nitrogen-to-albumin ratio (BAR) predict in-hospital mortality, ICU admission, and hemodialysis requirement within 48 hours in adults with cardiorenal syndrome presenting to the emergency department?

P

Population

201 adults (mean age 73.2 years, 51.2% female) presenting to a Turkish emergency department with confirmed cardiorenal syndrome and not on maintenance hemodialysis, evaluated retrospectively during hospitalization.

E

Exposure

Blood urea nitrogen-to-albumin ratio (BAR), calculated as BUN (mg/dL) divided by albumin (g/L) at emergency department admission

C

Comparator

BUN alone and serum albumin alone (in paired ROC curve comparisons)

O

Outcome

In-hospital mortality, intensive care unit (ICU) admission, and need for hemodialysis within the first 48 hours of admissionhard clinical

Main Result

Effect estimate: AUC 0.694 (95% CI 0.609-0.779)

Absolute Event Rate: 2.51% vs 1.75%

p-value: p=<0.001

In patients presenting to the emergency department with cardiorenal syndrome, the blood urea nitrogen-to-albumin ratio (BAR) was not associated with in-hospital mortality or ICU admission, and while associated with early hemodialysis requirement, it offered no discriminatory advantage over BUN alone.

Limitations

Retrospective, single-center design and restrictive exclusion criteria limit generalizability and may introduce selection bias
Potential confounders such as nutritional status, hydration, medication use, and liver function could not be fully controlled
Comparisons were unadjusted and exploratory without multivariable modeling or multiplicity correction
The ROC cutoff was derived and evaluated in the same cohort without internal or external validation
Hemodialysis is a clinician-dependent outcome that may be influenced directly by BUN levels
Creatinine-based eGFR may be unreliable during rapidly changing kidney function
Retrospective, single-center design and restrictive exclusions limit generalizability and may introduce selection bias
Nutritional status, hydration, medication use, liver function, and other potential confounders could not be fully controlled
Reported comparisons are unadjusted and involve multiple variables and outcomes, increasing the possibility of confounding and chance findings
The same cohort was used to derive the ROC cutoff and assess its performance, without internal or external validation
Hemodialysis is a clinician-dependent outcome that may be influenced by BUN and the severity of renal dysfunction

Implication

BAR may support early HD risk assessment in cardiorenal syndrome; leaves open its mortality utility and requires prospective validation.

Abstract

Background Cardiorenal syndrome (CRS) is a complex clinical condition characterized by bidirectional cardiac and renal dysfunction and associated with high morbidity and mortality. Given the limitations of existing cardiac and renal biomarkers, readily accessible prognostic indicators are needed. This study aimed to evaluate the association of the blood urea nitrogen-to-albumin ratio (BAR) with in-hospital mortality, intensive care unit (ICU) admission, and hemodialysis requirement in patients with CRS presenting to the emergency department. Methods This single-center retrospective study included 201 adults with cardiorenal syndrome presenting to a tertiary emergency department between May 1, 2023, and April 30, 2025. Clinical and laboratory characteristics were compared using Welch’s t-test or the Mann–Whitney U test. Receiver operating characteristic (ROC) analysis evaluated discrimination for hemodialysis within 48 hours; paired areas under the curve (AUCs) were compared using DeLong’s test. Results Mean age was 73.22 ± 11.99 years (n = 200), and 103 patients (51.2%) were female. In-hospital mortality occurred in 67 patients (33.3%), ICU admission in 105 (52.2%), and hemodialysis within 48 hours in 58 (28.9%). Median BAR was higher in patients requiring hemodialysis (2.51 vs. 1.75; p < 0.001). The AUC was 0.694 (95% confidence interval, 0.609–0.779). A cutoff of 2.64 yielded 48.3% sensitivity, 88.1% specificity, and a Youden index of 0.364. BAR did not differ significantly by mortality (p = 0.207) or ICU admission (p = 0.209). Its AUC was not significantly different from that of BUN (0.709; p = 0.230), but was higher than that of albumin (0.476; p < 0.001). Conclusions Higher BAR was associated with early hemodialysis requirement in unadjusted analyses, but superiority over BUN alone was not demonstrated. BAR did not differ significantly by mortality or ICU admission. Independent prognostic value and clinical utility require further evaluation.

Discussion

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Cite This Study

Dut et al. (2026) conducted an observational in Cardiorenal syndrome (n=201). Blood urea nitrogen-to-albumin ratio (BAR) vs. Blood urea nitrogen (BUN) or albumin alone / patients without clinical outcomes was evaluated on Hemodialysis requirement within 48 hours (AUC 0.694, 95% CI 0.609-0.779, p=<0.001). Blood urea nitrogen-to-albumin ratio showed modest discrimination for hemodialysis within 48 hours (AUC 0.694, p<0.001) in cardiorenal syndrome, but was not associated with mortality (p=0.207).

synapsesocial.com/papers/6ae28f41cbadf70daf6c4474 https://doi.org/10.21203/rs.3.rs-11152451/v1

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Association of the Blood Urea Nitrogen-to-Albumin Ratio with Clinical Outcomes in Patients with Cardiorenal Syndrome Presenting to the Emergency Department: A Retrospective Study

Key Points

Study Design

Structured PICO

Main Result

Limitations

Implication

Abstract

Discussion

Cite This Study

Association of the Blood Urea Nitrogen-to-Albumin Ratio with Clinical Outcomes in Patients with Cardiorenal Syndrome Presenting to the Emergency Department: A Retrospective Study

Key Points

Study Design

Structured PICO

Main Result

Limitations

Implication

Abstract

Discussion

Cite This Study

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