title: Accuracy of national mortality codes in identifying adjudicated cardiovascular deaths.
abstract: OBJECTIVE
  This study investigated the sensitivity and specificity of the national mortality codes in identifying cardiovascular disease (CVD) deaths and documents methods of verification.
  
  
  METHODS
  A 12-year retrospective case ascertainment of all ICD-coded CVD deaths was performed for deaths between 1990 and 2002 in the Melbourne Collaborative Cohort Study, comprising 41,528 subjects. Categories of non-CVD codes were also examined. Stratified samples of 750 deaths were adjudicated from a total of 2,230 deaths. Expert panels of cardiologists and neurologists adjudicated deaths.
  
  
  RESULTS
  Of the 750 deaths adjudicated, 582 were verified as CVD [392 coronary heart disease (CHD) and 92 stroke] and 168 non-CVD. Estimated sensitivity and specificity of national mortality codes for identifying specific causes of death were: CHD 74.2% (95% CI: 69.8-78.5%) and 97.6% (96.0-99.2%), respectively; myocardial infarction 59.9% (50.9-69.0%) and 94.2% (92.4-96.0%), respectively; haemorrhagic stroke 58.9% (46.0-71.7%) and 99.8% (99.4-100.0%), respectively and; ischaemic stroke 38.7% (20.5-56.9%) and 99.9% (99.6-100.0%), respectively. Misclassification was most common for deaths with primary ICD codes for endocrine-metabolic and genito-urinary diseases.
  
  
  CONCLUSIONS
  National mortality coding under-estimated the true proportion of CHD and stroke deaths in the cohort by 13.6% and 50.8%, respectively.
  
  
  CONCLUSIONS
  Misclassification of cause of death may have implications for conclusions drawn from epidemiological research.
authors.affiliation: Department of Epidemiology and Preventive Medicine, Monash University, Victoria. linton.harriss@monash.edu
authors.forename: Linton R
authors.initials: LR
authors.lastname: Harriss
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Ajani
authors.forename: David
authors.initials: D
authors.lastname: Hunt
authors.forename: James
authors.initials: J
authors.lastname: Shaw
authors.forename: Brian
authors.initials: B
authors.lastname: Chambers
authors.forename: Helen
authors.initials: H
authors.lastname: Dewey
authors.forename: Judith
authors.initials: J
authors.lastname: Frayne
authors.forename: Alison
authors.initials: A
authors.lastname: Beauchamp
authors.forename: Karen
authors.initials: K
authors.lastname: Duvé
authors.forename: Graham G
authors.initials: GG
authors.lastname: Giles
authors.forename: Stephen
authors.initials: S
authors.lastname: Harrap
authors.forename: Dianna J
authors.initials: DJ
authors.lastname: Magliano
authors.forename: Danny
authors.initials: D
authors.lastname: Liew
authors.forename: John
authors.initials: J
authors.lastname: McNeil
authors.forename: Anna
authors.initials: A
authors.lastname: Peeters
authors.forename: Margaret
authors.initials: M
authors.lastname: Stebbing
authors.forename: Rory
authors.initials: R
authors.lastname: Wolfe
authors.forename: Andrew
authors.initials: A
authors.lastname: Tonkin
mesh_terms: D000328:Adult; D000368:Aged; D001315:Australia / Q000453:epidemiology; D002318:Cardiovascular Diseases / Q000150:complications / Q000209:etiology / Q000401:mortality*; D002423:Cause of Death; D059019:Clinical Coding / Q000592:standards*; D003644:Death Certificates; D005260:Female; D006801:Humans; D038801:International Classification of Diseases; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012307:Risk Factors