Clinical study
The prognostic importance of anemia in patients with heart failure

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Abstract

Purpose

Physiologic studies have suggested that anemia could adversely affect the cardiovascular condition of patients with heart failure. Yet, the prognostic importance of this treatable condition is not well established by epidemiologic studies. We sought to determine the prognostic value of hematocrit level in a cohort of elderly patients hospitalized with heart failure.

Methods

We studied a consecutive sample of 2281 patients aged 65 years or older who had been admitted with a principal discharge diagnosis of heart failure. Multivariate Cox proportional hazards regression was conducted to test whether hematocrit level was an independent predictor of 1-year mortality and of hospital readmission.

Results

The mean (± SD) age of the patients was 79 ± 8 years; 58% (n = 1324) were women. Their median hematocrit was 38% (25th to 75th percentile, 33% to 42%). Lower hematocrits were associated with a higher mortality. After adjusting for demographic and clinical factors, each 1% lower hematocrit was associated with a 2% greater 1-year mortality (P = 0.007). Compared with patients with a hematocrit >42%, those with a hematocrit ≤27% had a 40% greater 1-year mortality (hazard ratio [HR] = 1.40; 95% confidence interval [CI]: 1.02 to 1.92; P = 0.04). This increased risk was similar to that conferred by traditional risk factors, including a left ventricular ejection fraction ≤20% (HR = 1.50; 95% CI: 1.20 to 1.86). Lower hematocrits were also associated with a greater risk of hospital readmission.

Conclusion

Anemia is associated with an increased risk of death and rehospitalization in older patients with heart failure. Whether anemia is a direct cause of worse outcomes, or a marker for other causal factors, is not known.

Section snippets

Sample

Patients were selected from Medicare’s National Claims History File for 18 acute care Connecticut hospitals from 1994 to 1995. A consecutive sample of 200 patients aged 65 years or older per hospital (or all cases from institutions with fewer than 200 admissions) who had a principal discharge diagnosis of heart failure (International Classification of Diseases, Ninth Revision [ICD-9], Clinical Modification codes 428 to 428.1, 402.01, 402.91, 404.01, 404.03, 404.11, 404.13, 404.91, and 404.93)

Results

The mean (± SD) age of the 2281 study patients was 79 ± 8 years; 58% (n = 1324) were women, and 90% (n = 2054) were white. The majority of patients had a history of hypertension (60%, n = 1358) and heart failure (63%, n = 1432), and a substantial minority had diabetes (37%, n = 839), a history of myocardial infarction (37%, n = 832), or a history of renal insufficiency (20%, n = 463). The median value for hematocrit was 38% (25th to 75th percentiles: 33% to 42%). Hematocrits were higher in men (

Discussion

Our study demonstrates that anemia is an independent predictor of mortality in a representative group of hospitalized elderly patients with heart failure. The magnitude of this effect was similar to other well-accepted predictors of adverse outcome in these patients, such as left ventricular ejection fraction. Anemia was also a significant predictor of 1-year hospital readmission.

Previous studies have identified other adverse prognostic factors among patients with heart failure, including low

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