title: Effect of erythropoietin levels on mortality in old age: the Leiden 85-plus Study.
abstract: BACKGROUND
  The production of erythropoietin is triggered by impaired oxygen delivery to the kidney, either because of anemia or hypoxemia. High erythropoietin levels have been shown to predict the risk of death among patients with chronic heart failure. We investigated the prognostic value of elevated erythropoietin levels on mortality among very elderly people in the general population.
  
  
  METHODS
  The Leiden 85-plus Study is a population-based prospective follow-up study involving 599 people aged 85 years in Leiden, the Netherlands, enrolled between September 1997 and September 1999. Erythropoietin levels were determined at age 86. For this analysis, we included 428 participants with a creatinine clearance of at least 30 mL/min. Mortality data, recorded until Feb. 1, 2008, were obtained from the municipal registry.
  
  
  RESULTS
  During follow-up, 324 (75.7%) participants died. Compared with participants whose erythropoietin levels were in the lowest tertile (reference group), those whose levels were in the middle tertile had a 25% increased risk of death (hazard ratio [HR] 1.25, 95% confidence interval [CI] 0.95-1.64), and those whose levels were in the highest tertile had a 73% increased risk (HR 1.73, 95% CI 1.32-2.26) (p value for trend < 0.01). The association between erythropoietin levels and mortality remained largely unchanged after we adjusted for sex, creatinine clearance, hemoglobin level, comorbidity, smoking status and C-reactive protein level, and was similar for deaths from cardiovascular and noncardiovascular causes.
  
  
  CONCLUSIONS
  Among people aged 85 years and older, elevated erythropoietin levels were associated with an increased risk of death, independent of hemoglobin levels.
authors.affiliation: Department of Public Health and Primary Care, Leiden University Medical Center, the Netherlands. w.p.j.den_elzen@lumc.nl
authors.forename: Wendy P J
authors.initials: WP
authors.lastname: den Elzen
authors.forename: Jorien M
authors.initials: JM
authors.lastname: Willems
authors.forename: Rudi G J
authors.initials: RG
authors.lastname: Westendorp
authors.forename: Anton J M
authors.initials: AJ
authors.lastname: de Craen
authors.forename: Gerard Jan
authors.initials: GJ
authors.lastname: Blauw
authors.forename: Luigi
authors.initials: L
authors.lastname: Ferrucci
authors.forename: Willem J J
authors.initials: WJ
authors.lastname: Assendelft
authors.forename: Jacobijn
authors.initials: J
authors.lastname: Gussekloo
mesh_terms: D000367:Age Factors; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood*; D000740:Anemia / Q000097:blood / Q000401:mortality*; D015415:Biomarkers / Q000097:blood; D002318:Cardiovascular Diseases / Q000097:blood / Q000401:mortality*; D002423:Cause of Death / Q000639:trends; D004921:Erythropoietin / Q000097:blood*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D009426:Netherlands / Q000453:epidemiology; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D015996:Survival Rate / Q000639:trends; D014505:Urban Population
chemical_list: D015415:Biomarkers; D004921:Erythropoietin