title: Nationwide individual record linkage study showed poor agreement of causes of death and hospital diagnoses at individual level but reasonable agreement at population level.
abstract: OBJECTIVE
  To investigate to what extent underlying and multiple causes of death represent end-of-life morbidity in individuals and at population level.
  
  
  METHODS
  Cause of death and national hospital data were individually linked for all deaths at the age of 50-84 years, in 2005 in the Netherlands (n = 86,987). The individual agreement of diseases registered as a diagnosis of discharge in the last 2 years of life and underlying and multiple causes of death recorded was assessed. Cause-of-death ranking was compared with ranking of hospital diagnoses.
  
  
  RESULTS
  The percentage of persons with a hospital diagnosis registered as the underlying cause of death was <30% for most diseases, except for cerebrovascular disease, chronic obstructive pulmonary disease and bronchiectasis, acute myocardial infarction (40-60%), and cancers (70-90%). Low Cohen's kappa values confirmed poor individual agreement between hospital diagnoses and underlying and secondary causes of death recorded. At population level, however, frequency rankings of underlying and multiple causes of death agreed reasonably well with frequency ranking of hospital diagnoses (Spearman ρ of 0.58-0.60 and 0.61-0.63).
  
  
  CONCLUSIONS
  Underlying and multiple causes of death poorly represent diseases present at the end of life in individuals but show reasonably well which diseases are most common at population level.
authors.affiliation: Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Dr. Molewaterplein 50, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands; Department of Epidemiology, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30 001, 9700 RB Groningen, The Netherlands. Electronic address: b.klijs01@umcg.nl.
authors.forename: Bart
authors.initials: B
authors.lastname: Klijs
authors.affiliation: Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Dr. Molewaterplein 50, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands.
authors.forename: Wilma J
authors.initials: WJ
authors.lastname: Nusselder
authors.affiliation: Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Dr. Molewaterplein 50, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands.
authors.forename: Johan P
authors.initials: JP
authors.lastname: Mackenbach
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002318:Cardiovascular Diseases / Q000175:diagnosis / Q000401:mortality; D002423:Cause of Death; D003625:Data Collection; D003933:Diagnosis; D005260:Female; D006761:Hospitals / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000175:diagnosis / Q000401:mortality; D009426:Netherlands / Q000453:epidemiology
keywords: Cause of death; Death certificates; Hospital records; Main diagnosis; Medical record linkage; Quality control