title: Risk matrix model for prediction of colectomy in a population-based study of ulcerative colitis patients (the IBSEN study).
abstract: OBJECTIVE
  Identifying ulcerative colitis (UC) patients with increased risk of colectomy is essential for appropriate treatment. We aimed to develop a prediction model assessing the risk of having colectomy within the first 10 years after diagnosis.
  
  
  METHODS
  A population-based inception cohort of UC patients diagnosed in south-eastern Norway between 1990 and 1994 has been followed for 10 years. Altogether 519 patients were recruited including 49 patients who were colectomized. Based on the best-fitted multivariate model, the probabilities of colectomy were computed for selected levels of baseline covariates, and the results arranged in a prediction matrix. The following risk factors at diagnosis were analyzed: age, smoking, sex, disease extent, weight loss and fever and need for systemic steroids. Biochemical markers included C-reactive protein (CRP, <30 or ≥30 mg/l); erythrocyte sedimentation rate (ESR, <30 or ≥30 mm/h) and hemoglobin (Hgb, <10.5 or ≥ 10.5 g/dL).
  
  
  RESULTS
  Extent of disease, age (<40 years, ≥40 years), need for systemic steroids and CRP or ESR (<30 or ≥30) at diagnosis were independently associated with colectomy and were combined in a prediction matrix. The probabilities of colectomy during the follow-up period ranged from 2.6% to 40.1% depending on the combination of predictors at diagnosis.
  
  
  CONCLUSIONS
  Our prediction model revealed significant differences in the probability of undergoing colectomy during a 10-years course of disease, which supports an early individualized treatment approach in UC.
authors.affiliation: Department of Gastroenterology, Division of Medicine, Oslo University Hospital , Oslo , Norway.
authors.forename: Inger Camilla
authors.initials: IC
authors.lastname: Solberg
authors.forename: Marte Lie
authors.initials: ML
authors.lastname: Høivik
authors.forename: Milada
authors.initials: M
authors.lastname: Cvancarova
authors.forename: Bjørn
authors.initials: B
authors.lastname: Moum
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood*; D001799:Blood Sedimentation; D002097:C-Reactive Protein / Q000737:chemistry; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003082:Colectomy / Q000379:methods*; D003093:Colitis, Ulcerative / Q000188:drug therapy* / Q000601:surgery*; D005260:Female; D005938:Glucocorticoids / Q000627:therapeutic use; D006454:Hemoglobins / Q000737:chemistry; D006801:Humans; D016015:Logistic Models; D008297:Male; D019804:Mesalamine / Q000627:therapeutic use; D008875:Middle Aged; D009664:Norway; D011379:Prognosis; D012307:Risk Factors; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D015415:Biomarkers; D005938:Glucocorticoids; D006454:Hemoglobins; D019804:Mesalamine; D002097:C-Reactive Protein
keywords: colectomy; population-based; prognosis; risk factors; ulcerative colitis