title: A prospective study of anemia status, hemoglobin concentration, and mortality in an elderly cohort: the Cardiovascular Health Study.
abstract: BACKGROUND
  Anemia is viewed as a negative prognostic factor in the elderly population; its independent impact on survival is unclear.
  
  
  METHODS
  Baseline hemoglobin quintiles and anemia, as defined by the World Health Organization criteria, were assessed in relation to mortality in the Cardiovascular Health Study, a prospective cohort study with 11.2 years of follow-up of 5888 community-dwelling men and women 65 years or older, enrolled in 1989-1990 or 1992-1993 in 4 US communities.
  
  
  RESULTS
  A total of 1205 participants were in the lowest hemoglobin quintile (<13.7 g/dL for men; <12.6 g/dL for women), and 498 (8.5%) were anemic (<13 g/dL for men; <12 g/dL for women). A reverse J-shaped relationship with mortality was observed; age-, sex-, and race-adjusted hazard ratios (95% confidence interval [CI]) in the first and fifth quintiles, compared with the fourth quintile, were 1.42 (95% CI, 1.25-1.62) and 1.24 (95% CI, 1.09-1.42). After multivariate adjustment, these hazard ratios were 1.33 (95% CI, 1.15-1.54) and 1.17 (95% CI, 1.01-1.36). The demographic- and fully-adjusted hazard ratios of anemia for mortality were 1.57 (95% CI, 1.38-1.78) and 1.38 (95% CI, 1.19-1.54). Adjustment for causes and consequences of anemia (renal function, inflammation, or frailty) did not reduce associations.
  
  
  CONCLUSIONS
  Lower and higher hemoglobin concentrations and anemia by World Health Organization criteria were independently associated with increased mortality. The World Health Organization criteria did not identify risk as well as a lower hemoglobin value. Additional study is needed on the clinically valid definition for and causes of anemia in the elderly and on the increased mortality at the extremes of hemoglobin concentrations.
authors.affiliation: Department of Medicine, University of Vermont College of Medicine and Fletcher Allen Health Care, Burlington, USA.
authors.forename: Neil A
authors.initials: NA
authors.lastname: Zakai
authors.forename: Ronit
authors.initials: R
authors.lastname: Katz
authors.forename: Calvin
authors.initials: C
authors.lastname: Hirsch
authors.forename: Michael G
authors.initials: MG
authors.lastname: Shlipak
authors.forename: Paulo H M
authors.initials: PH
authors.lastname: Chaves
authors.forename: Anne B
authors.initials: AB
authors.lastname: Newman
authors.forename: Mary
authors.initials: M
authors.lastname: Cushman
mesh_terms: D000367:Age Factors; D000368:Aged; D000740:Anemia / Q000097:blood / Q000401:mortality; D002140:California / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006304:Health Status; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D008297:Male; D008396:Maryland / Q000453:epidemiology; D015999:Multivariate Analysis; D009657:North Carolina / Q000453:epidemiology; D019370:Observation; D010414:Pennsylvania / Q000453:epidemiology; D011446:Prospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D015996:Survival Rate / Q000639:trends
chemical_list: D006454:Hemoglobins