Background: Elevated blood urea nitrogen (BUN) in chronic heart failure (CHF) patients may represent increased neurohormonal activation. The purpose of this work was to evaluate the prognostic value of BUN and its variation in ambulatory patients with stable CHF.
Methods: In a retrospective analysis we included 241 outpatients with stable CHF (NYHA class I-III). We evaluated patients at baseline and at 6 months, then they have been followed for one year. The population was divided in four groups according to the median value of BUN at baseline and BUN change (percentage) at 6 months (group 1 BUN <25.2 mg/dL and variation <3.4%, group 2 BUN <25.2 mg/dL and ≥3.4 %, group 3 BUN ≥25.2 mg/dL and <3.4%, group 4 BUN ≥25.2 mg/dL and ≥3.4%). During a median follow-up of one year, 3 (1.3%) patients died and 49 (20.3%) were hospitalized due to worsening heart failure HF.
Results: The Kaplan-Meier curve showed that group 3 and group 4 had worse prognosis compared with group 1 and 2 and that a greater change in BUN, was associated with a further worsening of the prognosis (group 4). Multivariable models confirmed that cardiovascular mortality and HF hospitalizations were more frequent in patients who had an increase of BUN (HR 1.011 [IC 95% 1.002-1.021]; P=0.015).
Conclusions: In ambulatory patients with stable chronic heart failure the increment of BUN is associated with increased cardiovascular mortality and heart failure hospitalizations at one-year.