Discharge BNP is a stronger predictor of 6-month mortality in acute heart failure compared with baseline BNP and admission-to-discharge percentage BNP reduction

Abstract

IntroductionPrior studies found a significant relationship between admission B-type natriuretic peptide (BNP), discharge BNP and admission-to-discharge percentage BNP reduction and post-discharge mortality in acute heart failure (HF). MethodsThe ESCAPE trial data was utilized to identify which of these BNP parameters best predicts 6-month all-cause mortality. Results433 patients (mean age 56years, 74% men) included in our analysis had an admission BNP, discharge BNP and admission-to-discharge percentage BNP reduction of 1009pg/mL, 743pg/mL and −70%, respectively. There were significant differences between survivors and nonsurvivors with regards to admission BNP (P=0.001), discharge BNP (P=0.0001) and admission-to-discharge percentage BNP reduction (P=0.01). Discharge BNP had the highest area under the curve (AUC) for predicting mortality (AUC=0.702, P<0.001) followed by admission BNP (AUC=0.633, P=0.0006) then percentage BNP reduction (AUC=0.620, P=0.008). Comparison of AUC revealed a significant difference between discharge BNP and admission BNP (difference between areas 0.087, P=0.0223) and a trend towards significance when comparing AUC of discharge BNP with percentage BNP reduction (P=0.0637). Kaplan–Meier analysis showed a significant difference in survival according to optimum cutoff values of discharge BNP of 319pg/mL (log-rank P<0.001), admission BNP of 912pg/mL (P<0.001) and percentage BNP reduction of 7.71% (P=0.008). Cox-proportional-hazard-analysis revealed that discharge BNP is an independent predictor of 6-month mortality (hazard ratio=1.063, 95% CI=1.037–1.089, P<0.001). The combination of a discharge BNP ≤319pg/mL and percentage BNP reduction ≥7.71% was associated with significantly lower mortality (4.8% versus 27.2%, relative risk=0.134, 95% CI=0.046–0.387, P<0.001). ConclusionThe absolute BNP value at discharge is a more accurate predictor of 6-month mortality than the magnitude of percentage in-hospital BNP reduction and baseline BNP.