title: An examination of subgroup classification in irritable bowel syndrome patients over time: a prospective study.
abstract: BACKGROUND
  Irritable bowel syndrome (IBS) is a complex functional gastrointestinal disorder which to date remains poorly understood. Therapies for irritable bowel syndrome (IBS) patients are usually aimed at relieving the predominant symptom; however, little evidence exists as to whether or not the predominant symptom changes with time. Nurses are becoming increasingly involved in the assessment and management of IBS patients.
  
  
  OBJECTIVE
  To categorise IBS patients into one of three sub-types, namely diarrhoea-predominant, constipation-predominant and a third group who alternate between the two, and to investigate changes in patient sub-type classification over time.
  
  
  METHODS
  Observational cohort study.
  
  
  METHODS
  The general population of the United Kingdom (UK).
  
  
  METHODS
  A cohort of 494 IBS patients, with a confirmed Rome II classification diagnosis, was recruited in the UK. Patients' IBS symptoms were recorded throughout a 26-week period. Proportions of individuals in each IBS subgroup were calculated and probabilities of moving from one subgroup to another between consecutive weeks were estimated.
  
  
  RESULTS
  The percentage of patients given an overall subgroup classification of diarrhoea-predominant IBD (D-IBS) is 40.9%; 58.1% and 1% were classified as belonging to the alternator (A-IBS) and constipation-predominant (C-IBS) subgroups, respectively.
  
  
  METHODS
  classified as an alternator or as diarrhoea-predominant have a high probability (0.67 and 0.71, respectively) of remaining in the same subgroup; however this probability is lower for constipation-predominant patients (0.35).
  
  
  CONCLUSIONS
  Although many patients remain in the same IBS subgroup classification over time, there are individuals whose subgroup classification varies. As such, patients' IBS subgroup classification should be reviewed regularly and treatment adjusted accordingly in order to optimise patient care.
authors.affiliation: Napier University, Edinburgh, UK.
authors.forename: Kay I
authors.initials: KI
authors.lastname: Penny
authors.forename: Graeme D
authors.initials: GD
authors.lastname: Smith
authors.forename: David
authors.initials: D
authors.lastname: Ramsay
authors.forename: Douglas T
authors.initials: DT
authors.lastname: Steinke
authors.forename: Moira
authors.initials: M
authors.lastname: Kinnear
authors.forename: Ian D
authors.initials: ID
authors.lastname: Penman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001294:Attitude to Health; D003248:Constipation / Q000209:etiology*; D003967:Diarrhea / Q000209:etiology*; D005260:Female; D006304:Health Status; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000145:classification* / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology*; D016014:Linear Models; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D009730:Nursing Assessment; D015995:Prevalence; D011336:Probability; D011446:Prospective Studies; D011795:Surveys and Questionnaires; D013997:Time Factors; D006113:United Kingdom / Q000453:epidemiology