title: Anemia and heart failure: a community study.
abstract: OBJECTIVE
  Anemia is an important comorbidity in heart failure and has been associated with increased mortality. The goals of this study were to define the prevalence of anemia in a community population with heart failure, examine trends in prevalence over time, and evaluate the role of anemia in patients with heart failure with preserved and reduced ejection fraction.
  
  
  METHODS
  Two cohorts of Olmsted County residents with heart failure were examined. The retrospective cohort included incident heart failure cases from 1979 to 2002 (n=1063). The prospective cohort included active heart failure cases from 2003 to 2006 (n=677). Clinical characteristics were collected. Anemia was defined by World Health Organization criteria.
  
  
  RESULTS
  The prevalence of anemia was 40% in the retrospective cohort and 53% in the prospective cohort. Anemia prevalence increased by an estimated 16% between 1979 and 2002 (P=.008) and was higher in those with preserved (> or =50%) versus reduced (<50%) ejection fraction (58% vs 48%, respectively, P<.001) from 2003 to 2006. Anemia was associated with a large increase in the risk of death (P<.001 both cohorts). The relationship between mortality and hemoglobin followed a J-shaped curve, with increased mortality with hemoglobin levels less than 14 mg/dL and greater than 16 mg/dL. In the prospective cohort, after adjustment for clinical characteristics, the hazard ratios (95% confidence interval) for death were 3.07 (1.26-6.82) in those with a hemoglobin level of 16 mg/dL or more and 2.39 (1.37-4.27) in those with a hemoglobin level less than 10 mg/dL, using hemoglobin 14 to 16 mg/dL as the referent.
  
  
  CONCLUSIONS
  In the community, half of patients with heart failure are anemic, and the prevalence of anemia has increased over time. Anemia is more prevalent in heart failure with preserved ejection fraction and is associated with a large increase in mortality.
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic and Foundation, Rochester, MN 55905, USA.
authors.forename: Shannon M
authors.initials: SM
authors.lastname: Dunlay
authors.forename: Susan A
authors.initials: SA
authors.lastname: Weston
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Redfield
authors.forename: Jill M
authors.initials: JM
authors.lastname: Killian
authors.forename: Véronique L
authors.initials: VL
authors.lastname: Roger
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000740:Anemia / Q000150:complications* / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D006333:Heart Failure / Q000150:complications* / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D012189:Retrospective Studies; D013997:Time Factors