title: Local and national electronic databases in Norway demonstrate a varying degree of validity.
abstract: OBJECTIVE
  The aim of the present study was to examine the validity of local and national electronic databases using medical records as gold Standard.
  
  
  METHODS
  All hospital admissions with ICD 9-code 820.X (hip fracture) in a 1-year period were identified in the electronic discharge registers of the hospitals in Oslo and in the national electronic database (The Norwegian Patient Register). Medical records for all patients identified by the discharge registers and the logbooks of the operating theater of the hospitals were retrieved, and the diagnosis was verified.
  
  
  RESULTS
  Compared with the total number of fractures confirmed in medical records, the electronic discharge register of one of the hospitals underestimated the number of fractures by 46%, whereas the two other overestimated the number by 17% and 19%. For the national electronic database, an overall overestimation of 19% was found.
  
  
  CONCLUSIONS
  The present findings question the validity of electronic databases and thus have implications for epidemiologic studies.
authors.affiliation: Department of Medicine, Centre of Endocrinology, Aker University Hospital, N-0514 Oslo, Norway. c.m.lofthus@ioks.uio.no
authors.forename: C M
authors.initials: CM
authors.lastname: Lofthus
authors.forename: I
authors.initials: I
authors.lastname: Cappelen
authors.forename: E K
authors.initials: EK
authors.lastname: Osnes
authors.forename: J A
authors.initials: JA
authors.lastname: Falch
authors.forename: I S
authors.initials: IS
authors.lastname: Kristiansen
authors.forename: A W
authors.initials: AW
authors.lastname: Medhus
authors.forename: L
authors.initials: L
authors.lastname: Nordsletten
authors.forename: H E
authors.initials: HE
authors.lastname: Meyer
mesh_terms: D000368:Aged; D016208:Databases, Factual / Q000592:standards*; D006620:Hip Fractures / Q000453:epidemiology* / Q000601:surgery; D006751:Hospital Information Systems / Q000592:standards*; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D016347:Medical Records Systems, Computerized / Q000592:standards*; D009664:Norway / Q000453:epidemiology; D010351:Patient Discharge / Q000706:statistics & numerical data; D040442:Public Health Informatics / Q000592:standards*; D012042:Registries / Q000592:standards*; D015203:Reproducibility of Results