Prognostic Value of Blood Urea Nitrogen in Patients Hospitalized With Worsening Heart Failure: Insights From the Acute and Chronic Therapeutic Impact of a Vasopressin Antagonist in Chronic Heart Failure (ACTIV in CHF) Study

Abstract Background Hospitalization for acute decompensated heart failure (ADHF) is associated with a high postdischarge mortality and readmission rate. The association between baseline blood urea nitrogen (BUN) and clinical outcomes in patients admitted for ADHF was evaluated in a post-hoc analysis of the ACTIV in CHF trial. Methods and Results Patients were categorized into quartiles according to baseline BUN. Cox proportional hazards regression was used to test the association between BUN, mortality, and death or readmission within 60 days. Patients in the highest quartile (>40 mg/dL) had the highest 60-day mortality (14.3%, 9.3%, 4.0%, 0%, respectively; P < .001) and the highest rate of death or heart failure hospitalization (30.0%, 21.3% 18.4%, 8.6%; P < .001). After adjustment for covariates, BUN was a statistically significant predictor of both mortality and the composite endpoint of death or heart failure hospitalization at 60 days after hospital discharge. Serum creatinine and estimated creatinine clearance did not predict mortality after covariate adjustment. Conclusions Higher baseline BUN is a powerful predictor of increased postdischarge mortality in patients hospitalized for heart failure, even in the absence of severe renal failure. Even mild to moderate elevations in baseline BUN were predictive. BUN remains an easily accessible risk stratification tool that physicians should closely monitor in the hospital setting.