title: Hospitalisation, surgical and medical recurrence rates in inflammatory bowel disease 2003-2011—a Danish population-based cohort study.
abstract: OBJECTIVE
  The aim of this study is to evaluate the cumulative probability of recurrence and admission rates in an inflammatory bowel disease (IBD) inception cohort diagnosed in 2003-2004.
  
  
  METHODS
  Data on medications, phenotypes and surgery for 513 individuals with ulcerative colitis (UC, n=300) and Crohn's disease (CD, n=213) were obtained from medical records and linked to population-based health administrative database information. The admission rates and cumulative probability of recurrences were estimated, and the association with the baseline factors and medication was tested.
  
  
  RESULTS
  The cumulative risk of first recurrence after 1, 5 and 7 years was 40%, 63%, and 66% in CD patients and 51%, 75%, and 79% in UC patients, respectively. The cumulative risk of first surgical relapse was 6%, 18%, and 23% at 1, 5 and 7 years in CD respectively. One hundred and CD patients (66%) and 142 UC patients (47%) had at least one IBD-related hospitalisation. The hospitalisation rate decreased from 7.0 days/person-year in year one to 0.9 day at year 5 in CD, and from 4.7 days to 0.4 days for UC patients. Age above 40, current smoking, stricturing behaviour, and disease localisation (colonic, ileocolonic, and upper-GI) at diagnosis were predictors of recurrence in CD. In UC, age above 40 and former smoker status were predictors of recurrence and left-sided and extensive colitis were predictors of first-time hospitalisation.
  
  
  CONCLUSIONS
  In an era of improved treatment options, the recurrence rates, but not the surgery or hospitalisation rates, have decreased for CD but not for UC. The phenotypic characteristics at diagnosis predict the risk of recurrence and hospitalisation.
authors.affiliation: Gastrounit, Medical Section, Hvidovre Hospital, Hvidovre, University of Copenhagen, Denmark. Electronic address: marianne@kajbaek.dk.
authors.forename: Marianne K
authors.initials: MK
authors.lastname: Vester-Andersen
authors.affiliation: Gastrounit, Medical Section, Hvidovre Hospital, Hvidovre, University of Copenhagen, Denmark. Electronic address: ida.vind@regionh.dk.
authors.forename: Ida
authors.initials: I
authors.lastname: Vind
authors.affiliation: Gastrounit, Medical Section, Hvidovre Hospital, Hvidovre, University of Copenhagen, Denmark. Electronic address: michelle_prosberg84@hotmail.com.
authors.forename: Michelle V
authors.initials: MV
authors.lastname: Prosberg
authors.affiliation: Department of Medical Gastroenterology, Rigshospitalet, Copenhagen, University of Copenhagen, Denmark. Electronic address: bobengtsson@dadlnet.dk2.
authors.forename: Bo G
authors.initials: BG
authors.lastname: Bengtsson
authors.affiliation: Department of Internal Medicine, Frederiksberg Hospital, Frederiksberg, University of Copenhagen, Denmark. Electronic address: tn@jtnautomatik.dk.
authors.forename: Thomas
authors.initials: T
authors.lastname: Blixt
authors.affiliation: Digestive Disease Centre, Medical Section, Herlev Hospital, Herlev, University of Copenhagen, Denmark. Electronic address: pia.munkholm@regionh.dk.
authors.forename: Pia
authors.initials: P
authors.lastname: Munkholm
authors.affiliation: Department of Epidemiological Research, National Health Surveillance and Research, Copenhagen Denmark. Electronic address: aso@ssi.dk.
authors.forename: Mikael
authors.initials: M
authors.lastname: Andersson
authors.affiliation: Department of Epidemiological Research, National Health Surveillance and Research, Copenhagen Denmark; Department of Clinical Epidemiology, University of Aalborg, Aalborg, Denmark. Electronic address: tjs@ssi.dk.
authors.forename: Tine
authors.initials: T
authors.lastname: Jess
authors.affiliation: Gastrounit, Medical Section, Hvidovre Hospital, Hvidovre, University of Copenhagen, Denmark. Electronic address: flemming.bendtsen@regionh.dk.
authors.forename: Flemming
authors.initials: F
authors.lastname: Bendtsen
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001379:Azathioprine / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003082:Colectomy; D003251:Constriction, Pathologic / Q000453:epidemiology; D003718:Denmark / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D007223:Infant; D015212:Inflammatory Bowel Diseases / Q000453:epidemiology / Q000628:therapy*; D008297:Male; D015122:Mercaptopurine / Q000627:therapeutic use; D008875:Middle Aged; D012008:Recurrence; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors; D055815:Young Adult
chemical_list: D007166:Immunosuppressive Agents; D014409:Tumor Necrosis Factor-alpha; D015122:Mercaptopurine; D001379:Azathioprine
keywords: Biological treatment; Epidemiology; Hospitalisation; Inflammatory bowel disease; Recurrence rates