title: Completeness and diagnostic validity of recording acute myocardial infarction events in primary care, hospital care, disease registry, and national mortality records: cohort study.
abstract: OBJECTIVE
  To determine the completeness and diagnostic validity of myocardial infarction recording across four national health record sources in primary care, hospital care, a disease registry, and mortality register.
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  21 482 patients with acute myocardial infarction in England between January 2003 and March 2009, identified in four prospectively collected, linked electronic health record sources: Clinical Practice Research Datalink (primary care data), Hospital Episode Statistics (hospital admissions), the disease registry MINAP (Myocardial Ischaemia National Audit Project), and the Office for National Statistics mortality register (cause specific mortality data).
  
  
  METHODS
  One country (England) with one health system (the National Health Service).
  
  
  METHODS
  Recording of acute myocardial infarction, incidence, all cause mortality within one year of acute myocardial infarction, and diagnostic validity of acute myocardial infarction compared with electrocardiographic and troponin findings in the disease registry (gold standard).
  
  
  RESULTS
  Risk factors and non-cardiovascular coexisting conditions were similar across patients identified in primary care, hospital admission, and registry sources. Immediate all cause mortality was highest among patients with acute myocardial infarction recorded in primary care, which (unlike hospital admission and disease registry sources) included patients who did not reach hospital, but at one year mortality rates in cohorts from each source were similar. 5561 (31.0%) patients with non-fatal acute myocardial infarction were recorded in all three sources and 11 482 (63.9%) in at least two sources. The crude incidence of acute myocardial infarction was underestimated by 25-50% using one source compared with using all three sources. Compared with acute myocardial infarction defined in the disease registry, the positive predictive value of acute myocardial infarction recorded in primary care was 92.2% (95% confidence interval 91.6% to 92.8%) and in hospital admissions was 91.5% (90.8% to 92.1%).
  
  
  CONCLUSIONS
  Each data source missed a substantial proportion (25-50%) of myocardial infarction events. Failure to use linked electronic health records from primary care, hospital care, disease registry, and death certificates may lead to biased estimates of the incidence and outcome of myocardial infarction.
  
  
  BACKGROUND
  NCT01569139 clinicaltrials.gov.
authors.affiliation: London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK. emily.herrett@lshtm.ac.uk
authors.forename: Emily
authors.initials: E
authors.lastname: Herrett
authors.forename: Anoop Dinesh
authors.initials: AD
authors.lastname: Shah
authors.forename: Rachael
authors.initials: R
authors.lastname: Boggon
authors.forename: Spiros
authors.initials: S
authors.lastname: Denaxas
authors.forename: Liam
authors.initials: L
authors.lastname: Smeeth
authors.forename: Tjeerd
authors.initials: T
authors.lastname: van Staa
authors.forename: Adam
authors.initials: A
authors.lastname: Timmis
authors.forename: Harry
authors.initials: H
authors.lastname: Hemingway
mesh_terms: D059019:Clinical Coding / Q000592:standards / Q000706:statistics & numerical data; D057286:Electronic Health Records / Q000592:standards* / Q000706:statistics & numerical data; D004739:England / Q000453:epidemiology; D016021:Epidemiologic Studies; D017052:Hospital Mortality; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D008498:Medical Record Linkage; D009203:Myocardial Infarction / Q000175:diagnosis / Q000401:mortality*; D015588:Observer Variation; D011320:Primary Health Care / Q000706:statistics & numerical data; D012042:Registries / Q000592:standards* / Q000706:statistics & numerical data