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The following is a summary of “Predictive value of blood urea nitrogen to creatinine ratio and estimated plasma volume status in heart failure,” published in the April 2025 issue of BMC Cardiovascular Disorders by Zheng et al. 

This study investigates the prognostic relevance of the blood urea nitrogen to creatinine ratio (BCR) and estimated plasma volume status (ePVS) in critically ill patients with heart failure admitted to the ICU. While both BCR and ePVS have been individually associated with adverse outcomes in HF, their combined predictive utility for long-term mortality remains inadequately understood.

A retrospective cohort analysis was conducted using data from the MIMIC-IV database, which comprises detailed clinical information on ICU admissions. The estimated plasma volume status (ePVS) was calculated using hemoglobin and hematocrit values based on the Duarte method derived from the Strauss formula. The primary endpoint was all-cause mortality (ACM) at one year following ICU admission. Receiver operating characteristic curve analysis was employed to determine optimal cutoff values for BCR and ePVS. Patients were stratified into groups based on these thresholds. Survival probabilities were evaluated using Kaplan-Meier analysis, while associations with mortality were quantified using multivariate Cox proportional hazards models. Restricted cubic spline models were used to assess dose-response relationships. Harrell’s C-statistic was utilized to evaluate the prognostic performance of the models.

A total of 11,066 patients with HF were included in the final analysis. The optimal thresholds for mortality prediction were identified as BCR >22.81 and ePVS >7.16 ml/g. BCR demonstrated a non-linear, J-shaped relationship with 1-year ACM, indicating increased mortality risk at both low and high extremes. In contrast, ePVS showed a linear association, with higher values corresponding to progressively greater risk. Multivariable Cox regression revealed that elevated BCR was significantly associated with increased risk of 1-year ACM (HR = 1.39; 95% CI: 1.30–1.49; P < 0.001), as was higher ePVS (HR = 1.09; 95% CI: 1.02–1.16; P = 0.012). Importantly, patients with concurrently elevated BCR and ePVS had a markedly higher risk of mortality compared to those with lower levels of both biomarkers (HR = 1.54; 95% CI: 1.40–1.69; P < 0.001). The combined use of BCR and ePVS improved prognostic discrimination, as reflected by enhanced Harrell’s C-statistic values.

Both BCR and ePVS independently serve as significant predictors of 1-year all-cause mortality in critically ill patients with heart failure. Their combined application provides superior prognostic accuracy compared to either marker alone, underscoring the potential value of incorporating both parameters into routine risk-stratification strategies in the ICU setting.

Source: bmccardiovascdisord.biomedcentral.com/articles/10.1186/s12872-025-04717-5