title: Characterizing abdominal pain in IBS: guidance for study inclusion criteria, outcome measurement and clinical practice.
abstract: BACKGROUND
  Although irritable bowel syndrome (IBS) is a multisymptom disorder, abdominal pain drives illness severity more than other symptoms. Despite consensus that IBS trials should measure pain to define study entry and determine efficacy, the optimal method of measuring pain remains uncertain.
  
  
  OBJECTIVE
  To determine whether combining information from multiple pain dimensions may capture the IBS illness experience more effectively than the approach of measuring 'pain predominance' or pain intensity alone.
  
  
  METHODS
  Irritable bowel syndrome patients rated dimensions of pain, including intensity, frequency, constancy, predominance, predictability, duration, speed of onset and relationship to bowel movements. We evaluated the impact of each dimension on illness severity using multivariable regression techniques.
  
  
  RESULTS
  Among the pain dimensions, intensity, frequency, constancy and predictability were strongly and independently associated with illness severity; the other dimensions had weaker associations. The clinical definition of 'pain predominance', in which patients define pain as their most bothersome symptom, was insufficient to categorize patients by illness severity.
  
  
  CONCLUSIONS
  Irritable bowel disease pain is multifaceted; some pain dimensions drive illness more than others. IBS trials should measure various pain dimensions, including intensity, constancy, frequency and predictability; this may improve upon the customary use of measuring pain as a unidimensional symptom in IBS.
authors.affiliation: Department of Gastroenterology, VA Greater Los Angeles Healthcare System, Los Angeles, CA, USA. bspiegel@mednet.ucla.edu
authors.forename: B M R
authors.initials: BM
authors.lastname: Spiegel
authors.forename: R
authors.initials: R
authors.lastname: Bolus
authors.forename: L A
authors.initials: LA
authors.lastname: Harris
authors.forename: S
authors.initials: S
authors.lastname: Lucak
authors.forename: W D
authors.initials: WD
authors.lastname: Chey
authors.forename: G
authors.initials: G
authors.lastname: Sayuk
authors.forename: E
authors.initials: E
authors.lastname: Esrailian
authors.forename: A
authors.initials: A
authors.lastname: Lembo
authors.forename: H
authors.initials: H
authors.lastname: Karsan
authors.forename: K
authors.initials: K
authors.lastname: Tillisch
authors.forename: J
authors.initials: J
authors.lastname: Talley
authors.forename: L
authors.initials: L
authors.lastname: Chang
mesh_terms: D015746:Abdominal Pain / Q000209:etiology* / Q000523:psychology; D000328:Adult; D005260:Female; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000150:complications* / Q000523:psychology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010147:Pain Measurement / Q000523:psychology*; D011446:Prospective Studies; D012720:Severity of Illness Index; D016896:Treatment Outcome
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