title: Clinical prognostic factors for disabling Crohn's disease: a systematic review and meta-analysis.
abstract: OBJECTIVE
  To identify demographic and clinical factors associated with disabling Crohn's disease (CD).
  
  
  METHODS
  A systematic review and meta-analysis of observational studies, focusing on the factors that can predict the prognosis of different outcomes of CD was undertaken. PubMed, ISI Web of Knowledge and Scopus were searched to identify studies investigating the above mentioned factors in adult patients with CD. Studies were eligible for inclusion if they describe prognostic factors in CD, with inclusion and exclusion criteria defined as follows. Studies with adult patients and CD, written in English and studying association between clinical factors and at least one prognosis outcome were included. Meta-analysis of effects was undertaken for the disabling disease outcome, using odds ratio (OR) to assess the effect of the different factors in the outcome. The statistical method used was Mantel-Haenszel for fixed effects. The 16-item quality assessment tool (QATSDD) was used to assess the quality of the studies (range: 0-42).
  
  
  RESULTS
  Of the 913 papers initially selected, sixty studies were reviewed and three were included in the systematic review and meta-analysis. The global QATSDD scores of papers were 18, 21 and 22. Of a total of 1961 patients enrolled, 1332 (78%) were classified with disabling disease five years after diagnosis. In two studies, age at diagnosis was a factor associated with disabling disease five years after diagnosis. Individuals under 40 years old had a higher risk of developing disabling disease. In two studies, patients who were treated with corticosteroids on the first flare developed disabling disease five years after diagnosis. Further, perianal disease was found to be relevant in all of the studies at two and five years after diagnosis. Finally, one study showed localization as a factor associated with disabling disease five years after diagnosis, with L3 being a higher risk factor. This meta-analysis showed a significantly higher risk of developing disabling disease at five years after initial diagnosis among patients younger than 40 years of age (OR = 2.47, 95%CI: 1.74-3.51), with initial steroid treatment for first flare (OR = 2.42, 95%CI: 1.87-3.11) and with perianal disease (OR = 2.00, 95%CI: 1.41-2.85).
  
  
  CONCLUSIONS
  Age at diagnosis, perianal disease, initial use of steroids and localization seem to be independent prognostic factors of disabling disease.
authors.affiliation: Health Information and Decision Sciences Department, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal.
authors.forename: Cláudia Camila
authors.initials: CC
authors.lastname: Dias
authors.forename: Pedro Pereira
authors.initials: PP
authors.lastname: Rodrigues
authors.forename: Altamiro
authors.initials: A
authors.lastname: da Costa-Pereira
authors.forename: Fernando
authors.initials: F
authors.lastname: Magro
mesh_terms: D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000328:Adult; D000367:Age Factors; D001004:Anus Diseases / Q000453:epidemiology; D015897:Comorbidity; D003424:Crohn Disease / Q000175:diagnosis* / Q000188:drug therapy / Q000453:epidemiology; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D011379:Prognosis; D012307:Risk Factors; D012720:Severity of Illness Index
chemical_list: D000305:Adrenal Cortex Hormones
keywords: Crohn’s disease; Disabling disease; Meta-analysis; Outcome; Prognostic factors; Systematic review