Predictive value of blood urea nitrogen to creatinine ratio and estimated plasma volume status in heart failure

Abstract

Background: The blood urea nitrogen to creatinine ratio (BCR) and estimated plasma volume status (ePVS) may be prognostic markers in heart failure (HF), but their combined efficacy is unclear. This research aims to determine the prognostic utility of BCR and ePVS in critically ill HF patients in the intensive care unit. Methods: Data from the MIMIC-IV database were analyzed. ePVS was calculated using hemoglobin and hematocrit levels with Strauss-derived Duarte method. The primary outcome was 1-year all-cause mortality (ACM). Receiver operating characteristic (ROC) curves identified cutoff values for BCR and ePVS. To assess the connection between BCR, ePVS, and 1-year ACM, the Kaplan-Meier (KM) method, Cox proportional hazards models, subgroup analysis, and limited cubic spline were employed. Harrell’s C statistic evaluated predictive power. Results: Among 11,066 participants, optimal thresholds for mortality were BCR > 22.81 and ePVS > 7.16 ml/g. BCR demonstrated a non-linear J-shaped correlation with ACM, while ePVS displayed a linear relationship. Multivariate Cox analysis indicated higher level of BCR was linked to higher 1-year ACM (HR = 1.39, 95% CI: 1.30–1.49, P < 0.001), as was increased level of ePVS (HR = 1.09, 95% CI: 1.02–1.16, P = 0.012). Notably, HF patients with both high BCR and ePVS faced a significantly greater mortality risk than those with lower levels of both markers (HR = 1.54, 95% CI: 1.40–1.69, P < 0.001). Combining BCR and ePVS improved prognostic accuracy. Conclusions: BCR and ePVS independently predict 1-year ACM in HF patients, with their combined use offering improved prognostic accuracy.