title: Inability of the Rome III criteria to distinguish functional constipation from constipation-subtype irritable bowel syndrome.
abstract: OBJECTIVE
  The Rome III classification system treats functional constipation (FC) and irritable bowel syndrome with constipation (IBS-C) as distinct disorders, but this distinction appears artificial, and the same drugs are used to treat both. This study's hypothesis is that FC and IBS-C defined by Rome III are not distinct entities.
  
  
  METHODS
  In all, 1,100 adults with a primary care visit for constipation and 1,700 age- and gender-matched controls from a health maintenance organization completed surveys 12 months apart; 66.2% returned the first questionnaire. Rome III criteria identified 231 with FC and 201 with IBS-C. The second survey was completed by 195 of the FC and 141 of the IBS-C cohorts. Both surveys assessed the severity of constipation and IBS, quality of life (QOL), and psychological distress.
  
  
  RESULTS
  (i) Overlap: if the Rome III requirement that patients meeting criteria for IBS cannot be diagnosed with FC is suspended, 89.5% of IBS-C cases meet criteria for FC and 43.8% of FC patients fulfill criteria for IBS-C. (ii) No qualitative differences between FC and IBS-C: 44.8% of FC patients report abdominal pain, and paradoxically IBS-C patients have more constipation symptoms than FC. (iii) Switching between diagnoses: by 12 months, 1/3 of FC transition to IBS-C and 1/3 of IBS-C change to FC.
  
  
  CONCLUSIONS
  Patients identified by Rome III criteria for FC and IBS-C are not distinct groups. Revisions to the Rome III criteria, possibly including incorporation of physiological tests of transit and pelvic floor function, are needed.
authors.affiliation: Department of Gastroenterology and Hepatology, National University Hospital, Singapore.
authors.forename: Reuben K
authors.initials: RK
authors.lastname: Wong
authors.forename: Olafur S
authors.initials: OS
authors.lastname: Palsson
authors.forename: Marsha J
authors.initials: MJ
authors.lastname: Turner
authors.forename: Rona L
authors.initials: RL
authors.lastname: Levy
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Feld
authors.forename: Michael
authors.initials: M
authors.lastname: von Korff
authors.forename: William E
authors.initials: WE
authors.lastname: Whitehead
mesh_terms: D000328:Adult; D000368:Aged; D003248:Constipation / Q000145:classification / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000145:classification / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D011446:Prospective Studies; D011788:Quality of Life; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires