title: No increased mortality risk in older persons with unexplained anaemia.
abstract: BACKGROUND
  in older persons, anaemia is associated with a number of unfavourable outcomes. In approximately 30% of older persons with anaemia, the cause of the anaemia is unexplained. We assessed the clinical differences between subjects with explained and unexplained anaemia and investigated whether these subjects have different mortality patterns compared with subjects without anaemia.
  
  
  METHODS
  observational prospective follow-up study.
  
  
  METHODS
  the Leiden 85-plus study.
  
  
  METHODS
  four hundred and ninety-one persons aged 86 years.
  
  
  METHODS
  the study population was divided in three groups: (i) no anaemia (reference group, n=377), (ii) explained anaemia (iron deficiency, folate deficiency, vitamin B12 deficiency, signs of myelodysplastic syndrome or renal failure, n=74) and (iii) unexplained anaemia, (n=40). Mortality risks were estimated with Cox-proportional hazard models.
  
  
  RESULTS
  haemoglobin levels were significantly lower in subjects with explained anaemia than in subjects with unexplained anaemia (P<0.01). An increased risk for mortality was observed in subjects with explained anaemia [HR: 1.93 (95% CI: 1.47-2.52), P<0.001], but not in subjects with unexplained anaemia [HR: 1.19 (95% CI: 0.85-1.69), P=0.31]. Adjusted analyses (sex, co-morbidity, MMSE, institutionalised and smoking) did not change the observed associations for both explained and unexplained anaemic subjects.
  
  
  CONCLUSIONS
  older subjects with unexplained anaemia had similar survival compared with non-anaemic subjects. Increased mortality risks were observed in subjects with explained anaemia compared with non-anaemic subjects.
authors.affiliation: Gerontology and Geriatrics, LUMC, Leiden, The Netherlands. j.m.willems@lumc.nl
authors.forename: Jorien M
authors.initials: JM
authors.lastname: Willems
authors.forename: Wendy P J
authors.initials: WP
authors.lastname: den Elzen
authors.forename: L Tom
authors.initials: LT
authors.lastname: Vlasveld
authors.forename: Rudi G J
authors.initials: RG
authors.lastname: Westendorp
authors.forename: Jacobijn
authors.initials: J
authors.lastname: Gussekloo
authors.forename: Anton J M
authors.initials: AJ
authors.lastname: de Craen
authors.forename: Gerard J
authors.initials: GJ
authors.lastname: Blauw
mesh_terms: D000367:Age Factors; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood*; D000740:Anemia / Q000097:blood / Q000401:mortality*; D018798:Anemia, Iron-Deficiency / Q000097:blood / Q000401:mortality; D005260:Female; D005494:Folic Acid Deficiency / Q000097:blood / Q000401:mortality; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D009190:Myelodysplastic Syndromes / Q000097:blood / Q000401:mortality; D009426:Netherlands / Q000453:epidemiology; D016016:Proportional Hazards Models; D011446:Prospective Studies; D051437:Renal Insufficiency / Q000097:blood / Q000401:mortality; D018570:Risk Assessment; D012307:Risk Factors; D014806:Vitamin B 12 Deficiency / Q000097:blood / Q000401:mortality