Anemia and Chronic Kidney Disease are Associated With Poor Outcomes in Heart Failure Patients

Jean-Christophe Luthi; W Dana Flanders; Michel Burnier; Bernard Burnand; William M McClellan

Disclosures

BMC Nephrology. 2006;7 

In This Article

Abstract

Background: Chronic kidney disease (CKD) has been linked to higher heart failure (HF) risk. Anemia is a common consequence of CKD, and recent evidence suggests that anemia is a risk factor for HF. The purpose of this study was to examine among patients with HF, the association between CKD, anemia and inhospital mortality and early readmission.
Methods: We performed a retrospective cohort study in two Swiss university hospitals. Subjects were selected based the presence of ICD-10 HF codes in 1999. We recorded demographic characteristics and risk factors for HF. CKD was defined as a serum creatinine ≥ 124 956;mol/L for women and ≥ 133 μmol/L for men. The main outcome measures were inhospital mortality and thirty-day readmissions.
Results: Among 955 eligible patients hospitalized with heart failure, 23.0% had CKD. Twenty percent and 6.1% of individuals with and without CKD, respectively, died at the hospital (p < 0.0001). Overall, after adjustment for other patient factors, creatinine and hemoglobin were associated with an increased risk of death at the hospital, and hemoglobin was related to early readmission.
Conclusion: Both CKD and anemia are frequent among older patients with heart failure and are predictors of adverse outcomes, independent of other known risk factors for heart failure.

Heart failure (HF) is a common and serious condition that affects more than four million people in the United States.[1] Approximately 400,000 new cases are diagnosed each year, with mortality 6 years after diagnosis of 80% in men and 65% in women.[1] In Europe, the prevalence of symptomatic heart failure in the general population is estimated to range from 0.4% to 2%.[2] In Switzerland, approximately 210,000 people have HF.[3] Chronic kidney disease (CKD) is also a major health problem resulting in considerably increased morbidity, mortality and in high costs.[4] Furthermore, in the last decade, the prevalence of both CKD,[5,6] and HF has been rising steadily.[7,8,9] Anemia is a frequent complication of chronic kidney disease, primarily due to failure of erythropoietin production to respond to decreased haemoglobin concentration.[10,11] Anemia has also been found to be a risk factor for cardiovascular disease and in particular for HF.[12,13] In a study conducted in one Swiss university hospital the prevalence of anemia among heart failure patients was 15%.[13]

Furthermore, several studies have also shown that anemia with the presence of heart failure was a predictor of poor outcome[14,15,16,17,18,19,20] and greater hospital expenses.[21] Moreover, two recent studies have shown that anemia associated with CKD were independent risk factors for one year mortality among patients with HF.[22,23] One study included only patients with left ventricular systolic dysfunction,[22] whereas patients with left ventricular diastolic dysfunction were also included in the other.[23] Independent associations between both CKD and anemia with increased risk of one-year mortality were found. In both studies, a 1% decrease in hematocrit was associated with a 2.5% increase in the 12 month risk of death.

The purpose of our study was to examine, among patients with HF, the combined association of CKD and anemia on adverse outcomes. To our knowledge, this is the first study using inhospital mortality and early readmission for this purpose.

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