title: Comparing the validity of different sources of information on emergency department visits: a latent class analysis.
abstract: BACKGROUND
  Emergency department (ED) use in Quebec may be measured from varied sources, eg, patient's self-reports, hospital medical charts, and provincial health insurance claims databases. Determining the relative validity of each source is complicated because none is a gold standard.
  
  
  OBJECTIVE
  We sought to compare the validity of different measures of ED use without arbitrarily assuming one is perfect.
  
  
  METHODS
  Data were obtained from a nursing liaison intervention study for frail seniors visiting EDs at 4 university-affiliated hospitals in Montreal.
  
  
  METHODS
  The number of ED visits during 2 consecutive follow-up periods of 1 and 4 months after baseline was obtained from patient interviews, from medical charts of participating hospitals, and from the provincial health insurance claims database.
  
  
  METHODS
  Latent class analysis was used to estimate the validity of each source. The impact of the following covariates on validity was evaluated: hospital visited, patient's demographic/clinical characteristics, risk of functional decline, nursing liaison intervention, duration of recall, previous ED use, and previous hospitalization.
  
  
  RESULTS
  The patient's self-report was found to be the least accurate (sensitivity: 70%, specificity: 88%). Claims databases had the greatest validity, especially after defining claims made on consecutive days as part of the same ED visit (sensitivity: 98%, specificity: 98%). The validity of the medical chart was intermediate. Lower sensitivity (or under-reporting) on the self-report appeared to be associated with higher age, low comorbidity and shorter length of recall.
  
  
  CONCLUSIONS
  The claims database is the most valid method of measuring ED use among seniors in Quebec compared with hospital medical charts and patient-reported use.
authors.affiliation: Technology Assessment Unit, McGill University Health Center, Montreal, Canada. nandini.dendukuri@mcgill.ca
authors.forename: Nandini
authors.initials: N
authors.lastname: Dendukuri
authors.forename: Jane
authors.initials: J
authors.lastname: McCusker
authors.forename: François
authors.initials: F
authors.lastname: Bellavance
authors.forename: Sylvie
authors.initials: S
authors.lastname: Cardin
authors.forename: Josée
authors.initials: J
authors.lastname: Verdon
authors.forename: Igor
authors.initials: I
authors.lastname: Karp
authors.forename: Eric
authors.initials: E
authors.lastname: Belzile
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003625:Data Collection / Q000379:methods; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D016330:Frail Elderly / Q000706:statistics & numerical data*; D006785:Hospitals, University / Q000706:statistics & numerical data; D006801:Humans; D007345:Insurance Claim Review; D008297:Male; D008499:Medical Records; D011792:Quebec / Q000453:epidemiology; D012107:Research Design; D012650:Self Disclosure; D014600:Utilization Review / Q000706:statistics & numerical data*