Associations of anemia and renal dysfunction with outcomes among patients hospitalized for acute decompensated heart failure with preserved or reduced ejection fraction

Abstract

Background and objectives: The relationship among anemia, renal dysfunction, left ventricular ejection fraction, and outcomes of patients hospitalized for acute decompensated heart failure is unclear. The aim of this study was to evaluate the association between cardiorenal anemia syndrome and postdischarge outcomes in patients hospitalized for heart failure with a preserved or reduced ejection fraction.

Design, setting, participants, & measurements: Of 4842 patients enrolled in the Acute Decompensated Heart Failure Syndromes Registry between April 1, 2007 and December 31, 2011, 4393 patients were evaluated to investigate the association among anemia, renal dysfunction, preserved or reduced ejection fraction, and the primary end point (mortality and readmission for heart failure since discharge). The patients were divided into four groups on the basis of eGFR and hemoglobin at discharge. The median follow-up period after discharge was 432 (range=253-659) days.

Results: The primary end point was reached in 37.6% and 34.8% of the preserved and reduced ejection fraction groups, respectively. After adjustment for multiple comorbidities, there was no significant association of either renal dysfunction or anemia alone with the primary end point in patients with preserved ejection fraction, but the combination of renal dysfunction and anemia was associated with a significantly higher risk than that without either condition (hazard ratio, 1.54; 95% confidence interval, 1.12 to 2.12; P<0.01). In patients with reduced ejection fraction, adjusted analysis showed that a significantly higher risk of the primary end point was associated with renal dysfunction alone (hazard ratio, 1.65; 95% confidence interval, 1.21 to 2.25; P=0.002) and also, renal dysfunction plus anemia relative to the risk without either condition (hazard ratio, 2.19; 95% confidence interval, 1.62 to 2.96; P<0.001).

Conclusions: The findings show that renal dysfunction combined with anemia is associated with an increased risk of adverse postdischarge outcomes in patients with preserved ejection fraction, whereas renal dysfunction is an independent predictor of the risk of adverse outcomes in patients with reduced ejection fraction, regardless of anemia.

Keywords: anemia; heart failure; kidney dysfunction.

Figure 1.

Kaplan–Meier estimates of the combined end point (mortality and readmission for HF) in four groups stratified by renal dysfunction and anemia at discharge. (A) Patients with HF and preserved EF. (B) Patients with HF and reduced EF. EF, ejection fraction; HF, heart failure.