title: Osteoporosis-related fracture case definitions for population-based administrative data.
abstract: BACKGROUND
  Population-based administrative data have been used to study osteoporosis-related fracture risk factors and outcomes, but there has been limited research about the validity of these data for ascertaining fracture cases. The objectives of this study were to: (a) compare fracture incidence estimates from administrative data with estimates from population-based clinically-validated data, and (b) test for differences in incidence estimates from multiple administrative data case definitions.
  
  
  METHODS
  Thirty-five case definitions for incident fractures of the hip, wrist, humerus, and clinical vertebrae were constructed using diagnosis codes in hospital data and diagnosis and service codes in physician billing data from Manitoba, Canada. Clinically-validated fractures were identified from the Canadian Multicentre Osteoporosis Study (CaMos). Generalized linear models were used to test for differences in incidence estimates.
  
  
  RESULTS
  For hip fracture, sex-specific differences were observed in the magnitude of under- and over-ascertainment of administrative data case definitions when compared with CaMos data. The length of the fracture-free period to ascertain incident cases had a variable effect on over-ascertainment across fracture sites, as did the use of imaging, fixation, or repair service codes. Case definitions based on hospital data resulted in under-ascertainment of incident clinical vertebral fractures. There were no significant differences in trend estimates for wrist, humerus, and clinical vertebral case definitions.
  
  
  CONCLUSIONS
  The validity of administrative data for estimating fracture incidence depends on the site and features of the case definition.
authors.affiliation: School of Public Health, University of Saskatchewan, Saskatoon, Canada. lisa.lix@usask.ca
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Lix
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Azimaee
authors.forename: Beliz Acan
authors.initials: BA
authors.lastname: Osman
authors.forename: Patricia
authors.initials: P
authors.lastname: Caetano
authors.forename: Suzanne
authors.initials: S
authors.lastname: Morin
authors.forename: Colleen
authors.initials: C
authors.lastname: Metge
authors.forename: David
authors.initials: D
authors.lastname: Goltzman
authors.forename: Nancy
authors.initials: N
authors.lastname: Kreiger
authors.forename: Jerilynn
authors.initials: J
authors.lastname: Prior
authors.forename: William D
authors.initials: WD
authors.lastname: Leslie
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D015994:Incidence; D038801:International Classification of Diseases; D016014:Linear Models; D008297:Male; D008350:Manitoba / Q000453:epidemiology; D008499:Medical Records; D008875:Middle Aged; D058866:Osteoporotic Fractures / Q000145:classification* / Q000453:epidemiology*; D009626:Terminology as Topic