B-Type Natriuretic Peptide: A Predictor for Mortality, Intensive Care Unit Length of Stay, and Hospital Length of Stay in Patients With Resolving Sepsis

Abstract

BackgroundB-type natriuretic peptide (BNP) is a hormone secreted by cardiomyocytes in response to myocardial ischemia, increased ventricular wall tension, and overload. BNP is utilized as a diagnostic and prognostic marker in congested heart failure (CHF). Its prognostic value in sepsis is unknown. The aim of this study is to determine if BNP correlates with increased in-hospital mortality for septic patients.MethodsThis was a retrospective study of 505 patients admitted for sepsis or severe sepsis or septic shock during the period of January 2013 and August 2014. Patients that received > 3 L of intravenous fluids on presentation were included. Intensive care unit length of stay (ICULOS), hospital length of stay (HLOS) and in-hospital mortality were measured. Mean BNP level was calculated and compared to ICULOS and HLOS and in-hospital mortality. Controlled variables included ejection fraction (measured by echocardiogram within 6 months of presentation), glomerular filtration rate (calculated by Cockroft-Gault equation), patient demographics, and lactic acid trends. Exclusion criteria were no echocardiogram within 6 months of admission, no BNP levels on admission, and no repeat lactate or rising lactate levels within 24 h to indicate worsening sepsis.ResultsPatients’ mean BNP with in-hospital mortality was 908 pg/mL as compared to mean BNP of 678 pg/mL in survivors. T-test comparisons were statistically significant (P = 0.0375). The Kaplan-Meier curve for BNP as a predictor for in-hospital mortality showed that for the first 25 days, patients with BNP higher than 500 pg/mL had a higher mortality than patients with BNP lower than 500 pg/mL. When comparing HLOS, there is a statistically significant correlation (P = 0.0046). A similar scatter plot was prepared for ICULOS which showed there was a weak positive correlation (r = 0.199).ConclusionSeptic patients with in-hospital mortality had an average BNP of 908 pg/mL and statistically significant higher HLOS.

The utility of brain natriuretic peptides in septic shock as markers for mortality and cardiac dysfunction: A systematic review

“…Of the 46 studies included in this review, 35 examined the association of brain natriuretic peptides (BNP, NT‐proBNP) with survival in patients with septic shock, presented in Table . The vast majority were prospective cohort studies.…”

“…This association was also evaluated by two studies in the setting of an RCT evaluating the use of 20% human albumin plus crystalloids or crystalloids alone in patients with severe sepsis or septic shock . In total, 30 studies, including the two conducted in the setting of the RCT, have found a significant association between elevated levels of brain natriuretic peptides and increased mortality …”

“…The primary outcome of this systematic review was to assess the utility of BNP and NT‐proBNP as prognostic markers in septic shock. Brain natriuretic peptides have been shown to be adequate predictors of mortality in septic shock by numerous studies . However, there are significant differences in the reported limits for an optimal cut‐off value, ranging from 210 to 800 ng/L for BNP, with suboptimal sensitivity and specificity .…”

“…Brain natriuretic peptides have been shown to be adequate predictors of mortality in septic shock by numerous studies. [14][15][16][17][18]20,21,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37]39,41,42,[45][46][47] However, there are significant differences in the reported limits for an optimal cut-off value, ranging from 210 to 800 ng/L for BNP, 18,25 with suboptimal sensitivity and specificity. 25 The best reported values for sensitivity and specificity The Newcastle-Ottawa scale 12 is used to evaluate non-randomised studies.…”

“…24,27 In total, 30 studies, including the two conducted in the setting of the RCT, have found a significant association between elevated levels of brain natriuretic peptides and increased mortality. [14][15][16][17][18]20,21,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37]39,41,42,[45][46][47] Various studies reported the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR), negative likelihood ratio (NLR) of BNP and NT-proBNP in predicting mortality in septic shock. Several cut-off values have been proposed for both markers, 18,25,37,39,41,46,47 with some reporting that low BNP cut-off values (190 ng/L) were associated with a 5.7-fold increased risk of death (95% confidence interval [CI], 1.78-27.48; P < 0.014), 41 whereas others using higher cut-off values (800 ng/L) considered BNP a poor predictor of outcome.…”