The utility of brain natriuretic peptide as a prognosticating marker in critical care patients

A Naidoo; K de Vasconcellos

doi:10.7196/SAJCC.2023.v39i3.1218

The utility of brain natriuretic peptide as a prognosticating marker in critical care patients

South Afr J Crit Care. 2023 Dec 13;39(3):e1218. doi: 10.7196/SAJCC.2023.v39i3.1218. eCollection 2023.

Authors

A Naidoo¹, K de Vasconcellos²

Affiliations

¹ Department of Internal Medicine, Nelson R Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa.
² Department of Critical Care, King Edward VIII Hospital, Durban, and Discipline of Anaesthesiology and Critical Care, School of Clinical Medicine, University of KwaZulu-Natal, Durban, South Africa.

Abstract

Background: Brain natriuretic peptide (BNP) is an established biomarker of morbidity and mortality in cardiac failure. Data also suggest potential prognostic utility in non-heart failure cohorts. The utility of BNP in predicting intensive care unit (ICU) outcomes has not been well evaluated in a mixed critical care population in the South African (SA) context.

Objectives: To evaluate the ability of BNP to predict ICU mortality in a heterogeneous critical care population in SA.

Methods: This was a retrospective observational study of 100 patients admitted to a multidisciplinary, closed, intensivist-run ICU in a tertiary academic hospital serving KwaZulu-Natal Province (1 January 2020 - 31 July 2022). Initial BNP was evaluated as a predictor of ICU mortality using univariate and multivariable analyses.

Results: There was a statistically significant difference in BNP between survivors and non-survivors in the cohort of patients without heart failure. The median initial BNP in the non-heart failure cohort was 411 (interquartile range (IQR) 116 - 848) ng/L in non-survivors, and 150 (44 - 356) ng/L in survivors (p=0.028). The optimal cut-off for BNP was determined as 366 ng/L. A BNP ≥366 ng/L was an independent predictor of ICU outcome.

Conclusion: This study highlights the potential utility of BNP as a predictor of ICU mortality in a heterogeneous ICU population, with the greatest utility in patients without heart failure. Further studies are required to confirm this finding.

Contribution of the study: The study is a retrospective, observational study conducted in multidisciplinary, closed, intensivist-run ICU at a tertiary academic hospital. It showed an elevated BNP is associated with increased ICU mortality, particularly in those without a baseline diagnosis of heart failure. This identifies the need for further prospective studies evaluating BNP as a prognostic marker in non-cardiac critically ill patients, and its utility as an addition in pre-existing ICU outcome prediction scores.

Keywords: Brain natriuretic peptide; ICU mortality; biomarker.