Role of urea to creatinine ratio in the prediction of outcomes in chronic heart failure

Abstract Background Renal function predicts events in chronic heart failure (HF). Urea to creatinine ratio (UCR) is a simple and cheap biomarker which correlates with neuroendocrine pathways. Objectives Evaluate the prognostic role of UCR in patients with chronic HF. Methodology 86 patients with chronic HF from an academic hospital were included (with reduced, mildly reduced or improved left ventricular ejection fraction). UCR was calculated at baseline, and patients were followed for a median of 360 (interquartile range 180-472) days. We plotted ROC curves for NT-proBNP and UCR and evaluated two scenarios using the Kaplan-Meier curve to determine the event-free survival. We grouped patients into four subgroups: a) UCR and NT-proBNP below the cut-off; b) UCR above and NT-proBNP below; c) UCR below and NT-proBNP above; and d) both above the cut-off. A second scenario was analysed, grouped as follows: a) UCR and NT-proBNP below; b) at least one of them above the cut-off; and c) both above the cutoff. The primary endpoint was cardiovascular death or HF hospitalisation. The level of significance was 5%. Results The mean age was 66.1±12.1y, and 60.5% were male. There were 28 events in the follow-up (32.5%). The ROC curve for UCR had an AUC of 0.75 (CI 0.64-0.86; p=0.0002) for a cut-off of 43.8 (sensitivity of 75% and specificity of 70.7%). The AUC for NT-proBNP was 0.64 (0.51-0.77; p=0.043) for a cut-off of 2010 pg/mL (sensitivity of 64.3% and specificity of 65.5%). In the Cox regression model, the UCR was the only independent predictor with HR of 1.06 per 1 unit increase (1.03-1.10; p=0.0002). UCR above cut-off (as a categorical variable) was the only independent predictor, with HR 5.34 (2.26-12.6; p=0.0001). Kaplan-Meier curves in Figures 1 and 2 show the UCR performance associated with NT-proBNP. Conclusions UCR is a simple and cheap biomarker that has been shown to have predictive power, probably due to persistent neuroendocrine activation in patients with low volume. In this population, elevated UCR added risk even in patients with low levels of NT-proBNP.