B-type natriuretic peptide (BNP) decrease during hospitalization has been related to reduced risk of readmission and death in patients with acute heart failure (AHF). Conversely, the exact role of blood urea nitrogen (BUN) is still debated. Currently, no data have been published regarding the relation between these two biomarkers and the relation between them and clinical signs of congestion.Methods
We consecutively studied 107 patients with diagnosis of AHF and systolic dysfunction. All patients were observed during a 6-month follow-up period. BUN and BNP were measured according to the decrease of BNP levels at discharge of greater than 30% with respect to basal values; the persistence of congestion signs at discharge and BUN increase at discharge to more than 20% with respect to baseline.Results
In all patients mean BNP was 1014 ± 767 pg/ml; in patients with severe systolic dysfunction BNP was higher (1382 ± 1025 vs. 848 ± 549; P = 0.002). Mean BUN in all patients was 93 ± 42 mg/dl; BUN was higher in patients affected by chronic kidney disease compared with patients with preserved renal function (114 ± 45 vs. 68 ± 21 mg/dl; P < 0.001). Cox regression analysis demonstrated that BNP decrease of at least 30% together with congestion signs resolution was related to outcome improvement (univariate hazard ratio: 0.45 [0.19–0.97], P = 0.05; multivariate hazard ratio: 0.44 [0.20–0.98], P = 0.05). BUN increase of greater than 20% at discharge was associated with poor outcome independent of persistence of congestion signs (univariate hazard ratio: 2.72 [1.03–7.28], P = 0.04; multivariate hazard ratio: 3.00 [1.12–8.06], P = 0.03). Changes (Δ) of both BNP (univariate hazard ratio: 1.30 [1.04–1.61], P = 0.01) and BUN (univariate hazard ratio: 5.24 [1.72–15.95], P = 0.003) were associated with mortality, independently of congestion.Conclusions
In patients with AHF, BNP reduction of greater than 30% during hospitalization is associated with outcome improvement only if it occurs together with congestion resolution. Conversely, BUN increase of more than 20% was associated with poor outcome, independently of the persistence of congestion signs.