title: Evaluating the predictive value of osteoarthritis diagnoses in an administrative database.
abstract: OBJECTIVE
  To assess the positive and negative predictive values of osteoarthritis (OA) diagnoses contained in an administrative database.
  
  
  METHODS
  We identified all members (> or =18 years of age) of a Massachusetts health maintenance organization with documentation of at least one health care encounter associated with an OA diagnosis during the period 1994-1996. From this population, we randomly selected 350 subjects. In addition, we randomly selected 250 enrollees (proportionally by the age and sex of the 350 subjects) who did not have a health care encounter associated with an OA diagnosis. Trained nurse reviewers abstracted OA-related clinical, laboratory, and radiologic data from the medical records of both study groups (all but 1 chart was available for review). Pairs of physician reviewers evaluated the abstracted information for both groups of subjects and rated the evidence for the presence of OA according to 3 levels: definite, possible, and unlikely.
  
  
  RESULTS
  Among the group of patients with an administrative diagnosis of OA, 215 (62%) were rated as having definite OA, 36 (10%) possible OA, and 98 (28%) unlikely OA, according to information contained in the medical record. The positive predictive value of an OA diagnosis was 62%. In those without an administrative OA diagnosis, 44 (18%) were assigned a rating of definite OA. The negative predictive value of the absence of an administrative OA diagnosis was 78%.
  
  
  CONCLUSIONS
  Use of administrative data in epidemiologic and health services research on OA may lead to both case misclassification and under ascertainment.
authors.affiliation: Meyers Primary Care Institute, Fallon Healthcare System, and the University of Massachusetts Medical School, Worcester 01608, USA.
authors.forename: L R
authors.initials: LR
authors.lastname: Harrold
authors.forename: R A
authors.initials: RA
authors.lastname: Yood
authors.forename: S E
authors.initials: SE
authors.lastname: Andrade
authors.forename: J I
authors.initials: JI
authors.lastname: Reed
authors.forename: J
authors.initials: J
authors.lastname: Cernieux
authors.forename: W
authors.initials: W
authors.lastname: Straus
authors.forename: M
authors.initials: M
authors.lastname: Weeks
authors.forename: B
authors.initials: B
authors.lastname: Lewis
authors.forename: J H
authors.initials: JH
authors.lastname: Gurwitz
mesh_terms: D000368:Aged; D016001:Confidence Intervals; D016208:Databases, Factual / Q000592:standards; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000175:diagnosis* / Q000453:epidemiology; D011237:Predictive Value of Tests; D015995:Prevalence; D012744:Sex Ratio