title: Crohn's disease and ulcerative colitis in England and the Oxford record linkage study area: a profile of hospitalized morbidity.
abstract: BACKGROUND
  Crohn's disease and ulcerative colitis are chronic relapsing conditions. National hospital statistics in England only provide episode-based admission rates and cannot be used to identify multiple admissions per person. We used record linkage to provide a person-based profile of admission rates.
  
  
  METHODS
  Age-standardized admission rates were calculated from the computer tapes of the Hospital In-patient Enquiry (HIPE) for 1970-1985 and the Oxford Record Linkage Study (ORLS) for the period 1970-1986. In addition, annual hospitalized prevalence, first hospital admission rates (as a proxy for incidence) and readmission rates were calculated for the Oxford population. Predictors of relapses were assessed by logistic regression models.
  
  
  RESULTS
  Episode-based admission rates for Crohn's disease increased over time, both nationally and in Oxford. In Oxford, hospitalized incidence rates showed no increase for Crohn's disease. Neither episode-based nor person-based rates increased for ulcerative colitis. Relapses resulting in hospital admission were more common for Crohn's disease than for ulcerative colitis. They increased over time. We showed the influence of some sociodemographic characteristics (age, social class, district of residence, operations) on relapses.
  
  
  CONCLUSIONS
  Data on episodes of hospital care for Crohn's disease showed an increase over time while data related to individuals in receipt of care showed no increase over time. Unlinked episodes of hospital care are of limited value when studying temporal trends for chronic conditions with multiple admissions.
authors.affiliation: Department of Public Health and Primary Care, University of Oxford, UK.
authors.forename: P
authors.initials: P
authors.lastname: Primatesta
authors.forename: M J
authors.initials: MJ
authors.lastname: Goldacre
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D003093:Colitis, Ulcerative / Q000401:mortality*; D003424:Crohn Disease / Q000401:mortality*; D003625:Data Collection / Q000379:methods*; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D016013:Likelihood Functions; D016015:Logistic Models; D008297:Male; D008498:Medical Record Linkage; D008875:Middle Aged; D010343:Patient Admission; D010359:Patient Readmission; D015995:Prevalence; D012189:Retrospective Studies; D012744:Sex Ratio; D012959:Socioeconomic Factors; D013997:Time Factors; D014852:Wales / Q000453:epidemiology