B-type natriuretic peptide as a predictor of outcome in a general intensive care unit

BACKGROUND B-type natriuretic peptide is a hormone secreted by the heart in response to ventricular wall stress. Increased B-type natriuretic peptide plasma levels are also found as a consequence of noncardiac conditions including sepsis, surgery-induced systemic inflammatory response syndrome and kidney failure. Since these conditions are common in general intensive care unit patients, we hypothesized that B-type natriuretic peptide could be a helpful marker in predicting outcome in this setting. METHODS We measured plasma B-type natriuretic peptide concentrations in 228 patients at admission to our general intensive care unit. The primary aim of the study was to investigate the relationship between B-type natriuretic peptide and hospital mortality. The secondary aim of the study was to investigate the association between B-type natriuretic peptide and severity of disease, quantified by the Simplified Acute Physiology Score II. RESULTS Logistic regression revealed a positive association between B-type natriuretic peptide level and in-hospital death (OR= 1.59; 95% CI 1.30 to 1.95; p<0.0001) and a Cox proportional hazards regression model showed that B-type natriuretic peptide was significantly associated with the risk of death (HR=1.27; 95% CI 1.11 to 1.46; p=0.0005). B-type natriuretic peptide was higher in patients who died in the hospital than in those who survived (371.20 pg/ml vs. 127.10 pg/ml; p<0.0001). There was a positive correlation between B-type natriuretic peptide and Simplified Acute Physiology Score II (r=0.50; 95% CI 0.40 to 0.59; p<0.0001). DISCUSSION B-type natriuretic peptide on admission is an independent prognostic marker of outcome in an unselected cohort of critically ill patients.