Admission or Changes in Renal Function During Hospitalization for Worsening Heart Failure Predict Postdischarge Survival

Abstract

Background— Admission measures of renal function (blood urea nitrogen [BUN], estimated glomerular filtration rate [eGFR]) in patients hospitalized for worsening heart failure are predictors of in-hospital outcomes. Less is known about the changes and relationships among these variables and the postdischarge survival rate. Methods and Results— In a retrospective analysis of 949 patients from the Outcomes of a Prospective Trial of Intravenous Milrinone for Exacerbations of Chronic Heart Failure, we investigated the relation between admission values and changes in BUN and eGFR and rate of death by 60 days after discharge. On admission, median eGFR was 51 mL � min −1 � 1.73 m −2 (interquartile range, 37 to 70 mL � min −1 � 1.73 m −2 ), and BUN was 25 mg/dL (interquartile range, 17 to 41 mg/dL). On average, there was a 1.1–mL � min −1 � 1.73 m −2 decrease in eGFR and a 4.7-mg/dL increase in BUN from admission to discharge. By discharge, 12% of patients had a >25% decrease in eGFR, and 39% had a >25% increase in BUN. Although both lower admission eGFR and higher admission BUN were associated with higher risk of death by 60 days after discharge, multivariable-adjusted Cox proportional-hazards analysis showed that BUN was a stronger predictor of death by 60 days than was eGFR (χ 2 , 11.6 and 0.6 for BUN and eGFR, respectively). Independently of admission values, an increase of ≥10 mg/dL in BUN during hospitalization was associated with worse 60-day survival rate: BUN (per 5-mg/dL increase) had a hazard ratio of 1.08 (95% CI, 1.01 to 1.16). Although milrinone treatment led to a minor improvement in renal function by discharge, the 60-day death and readmission rates were similar between the milrinone and placebo groups. Conclusions— A substantial number of patients admitted with heart failure have worsening renal function during hospitalization. Higher admission BUN and increasing BUN during hospitalization, independently of admission values, are associated with a worse survival rate. Use of milrinone in these high-risk patients does not improve outcomes despite minor improvements in the renal function.