title: Rectal hypersensitivity as hallmark for irritable bowel syndrome: defining the optimal cutoff.
abstract: BACKGROUND
  Visceral hypersensitivity is a frequently observed hallmark of irritable bowel syndrome (IBS). Studies have reported differently about the presence of visceral hypersensitivity in IBS resulting from lack of standardization of the barostat procedure and due to different criteria used to assess hypersensitivity. We aimed to calculate the optimal cutoff to detect visceral hypersensitivity in IBS.
  
  
  METHODS
  A total of 126 IBS patients and 30 healthy controls (HC) were included for assessment of visceroperception by barostat. Pain perception was assessed on a visual analogue scale (VAS). ROC-curves were used to calculate optimal discriminative cutoff (pressure and VAS-score) between IBS patients and HC to define hypersensitivity. Furthermore, pain perception to distension sequences below the pressure threshold for hypersensitivity was defined as allodynia.
  
  
  RESULTS
  Irritable bowel syndrome patients showed increased visceroperception compared to HC. Thresholds for first sensation and first pain were lower in IBS patients VS HC (P < 0.01). ROC-curves showed optimal discrimination between IBS patients and HC at 26 mmHg with a VAS cutoff ≥20 mm. Using this criterion, hypersensitivity percentages were 63.5% and 6.6% in IBS patients and HC, respectively. No significant differences were observed between IBS subtypes. Allodynia was found in a small number of patients (11%).
  
  
  CONCLUSIONS
  Optimal cutoff for visceral hypersensitivity was found at pressure 26 mmHg with a VAS ≥20 mm, resulting in 63.5% of IBS patients being hypersensitive and 11% being allodynic. Standardization of barostat procedures and defining optimal cutoff values for hypersensitivity is warranted when employing rectal barostat measurements for research or clinical purposes.
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology and Hepatology, Maastricht University Medical Center+, Maastricht, The Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: Ludidi
authors.forename: J M
authors.initials: JM
authors.lastname: Conchillo
authors.forename: D
authors.initials: D
authors.lastname: Keszthelyi
authors.forename: M
authors.initials: M
authors.lastname: Van Avesaat
authors.forename: J W
authors.initials: JW
authors.lastname: Kruimel
authors.forename: D M
authors.initials: DM
authors.lastname: Jonkers
authors.forename: A A M
authors.initials: AA
authors.lastname: Masclee
mesh_terms: D000328:Adult; D019540:Area Under Curve; D005260:Female; D006801:Humans; D006930:Hyperalgesia / Q000209:etiology*; D043183:Irritable Bowel Syndrome / Q000150:complications / Q000175:diagnosis*; D008297:Male; D008365:Manometry / Q000379:methods; D010147:Pain Measurement; D017288:Pain Threshold; D012372:ROC Curve; D012007:Rectum