title: The risk of disabling, surgery and reoperation in Crohn's disease - A decision tree-based approach to prognosis.
abstract: BACKGROUND
  Crohn's disease (CD) is a chronic inflammatory bowel disease known to carry a high risk of disabling and many times requiring surgical interventions. This article describes a decision-tree based approach that defines the CD patients' risk or undergoing disabling events, surgical interventions and reoperations, based on clinical and demographic variables.
  
  
  METHODS
  This multicentric study involved 1547 CD patients retrospectively enrolled and divided into two cohorts: a derivation one (80%) and a validation one (20%). Decision trees were built upon applying the CHAIRT algorithm for the selection of variables.
  
  
  RESULTS
  Three-level decision trees were built for the risk of disabling and reoperation, whereas the risk of surgery was described in a two-level one. A receiver operating characteristic (ROC) analysis was performed, and the area under the curves (AUC) Was higher than 70% for all outcomes. The defined risk cut-off values show usefulness for the assessed outcomes: risk levels above 75% for disabling had an odds test positivity of 4.06 [3.50-4.71], whereas risk levels below 34% and 19% excluded surgery and reoperation with an odds test negativity of 0.15 [0.09-0.25] and 0.50 [0.24-1.01], respectively. Overall, patients with B2 or B3 phenotype had a higher proportion of disabling disease and surgery, while patients with later introduction of pharmacological therapeutic (1 months after initial surgery) had a higher proportion of reoperation.
  
  
  CONCLUSIONS
  The decision-tree based approach used in this study, with demographic and clinical variables, has shown to be a valid and useful approach to depict such risks of disabling, surgery and reoperation.
authors.affiliation: Department of Community Medicine, Information and Decision in Health, Faculty of Medicine of the University of Porto, Porto, Portugal.|CINTESIS - Center for Health Tecnology and Services Research, Porto, Portugal.
authors.forename: Cláudia Camila
authors.initials: CC
authors.lastname: Dias
authors.affiliation: Department of Community Medicine, Information and Decision in Health, Faculty of Medicine of the University of Porto, Porto, Portugal.|CINTESIS - Center for Health Tecnology and Services Research, Porto, Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Pereira Rodrigues
authors.affiliation: Centro Hospitalar Lisboa Norte, Hospital de Santa Maria, Lisboa, Portugal.
authors.forename: Samuel
authors.initials: S
authors.lastname: Fernandes
authors.affiliation: Gastroenterology Department, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal.
authors.forename: Francisco
authors.initials: F
authors.lastname: Portela
authors.affiliation: Gastroenterology Department, Centro Hospitalar Tondela e Viseu, Viseu, Portugal.
authors.forename: Paula
authors.initials: P
authors.lastname: Ministro
authors.affiliation: Gastroenterology Department, Centro Hospitalar Tondela e Viseu, Viseu, Portugal.
authors.forename: Diana
authors.initials: D
authors.lastname: Martins
authors.affiliation: Gastroenterology Department, Centro Hospitalar Tondela e Viseu, Viseu, Portugal.
authors.forename: Paula
authors.initials: P
authors.lastname: Sousa
authors.affiliation: Gastroenterology Department, Centro Hospitalar do Porto, Porto, Portugal.
authors.forename: Paula
authors.initials: P
authors.lastname: Lago
authors.affiliation: IPO Lisboa, Lisboa, Portugal.
authors.forename: Isadora
authors.initials: I
authors.lastname: Rosa
authors.affiliation: Centro Hospitalar Lisboa Norte, Hospital de Santa Maria, Lisboa, Portugal.
authors.forename: Luis
authors.initials: L
authors.lastname: Correia
authors.affiliation: Centro Hospitalar Lisboa Norte, Hospital de Santa Maria, Lisboa, Portugal.
authors.forename: Paula
authors.initials: P
authors.lastname: Moura Santos
authors.affiliation: Gastroenterology Department, Hospital São João, Porto, Portugal.|Institute of Pharmacology and Therapeutics Faculty of Medicine of the University of Porto, Porto, Portugal.|MedInUP - Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal.
authors.forename: Fernando
authors.identifier: http://orcid.org/0000-0003-2634-9668
authors.initials: F
authors.lastname: Magro
mesh_terms: D000293:Adolescent; D000328:Adult; D003424:Crohn Disease / Q000601:surgery*; D003663:Decision Trees; D013505:Digestive System Surgical Procedures / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007422:Intestines / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012086:Reoperation; D012189:Retrospective Studies; D055815:Young Adult