title: Validation and modification of a diagnostic scoring system to predict microscopic colitis.
abstract: OBJECTIVE
  Many patients with diarrhoea undergo colonoscopy. If this is macroscopically normal, random biopsies are obtained to rule out microscopic colitis (MC), but most patients have functional disease. Accurate predictors of MC could avoid the need to take biopsies in a substantial proportion of patients, saving money for the health service. We validated a previously described diagnostic scoring system for MC, and incorporated further variables to assess whether this improved performance.
  
  
  METHODS
  Consecutive adults with loose stools undergoing colonoscopy in Leeds, UK were included. Demographic and symptom data were collected prospectively. The diagnostic scoring system described previously was applied. In addition, the incorporation of further variables, including drugs associated with MC, number of stools, nocturnal passage of stools, and duration of loose stools, into the scoring system was assessed. Sensitivities, specificities, and positive and negative predictive values were calculated.
  
  
  RESULTS
  Among 242 patients (mean age 51.0 years, 163 (67.4%) female), 26 (10.7%) of whom had MC, a cut off of ≥4 on the original scoring system had a sensitivity of 92.3% and specificity of 35.2%. Nocturnal passage of stools and duration of loose stools <6 months were significant predictors of MC. Incorporating these variables in a new scoring system with a cut off of ≥6 identified MC with 95.7% sensitivity and 46.0% specificity.
  
  
  CONCLUSIONS
  Incorporating nocturnal passage of stools and duration of loose stools into the scoring system may improve ability to predict MC, and avoid random colonic biopsies in a greater proportion of patients with loose stools.
authors.affiliation: a Leeds Gastroenterology Institute, St. James's University Hospital , Leeds , UK ;|b Leeds Institute of Biomedical and Clinical Sciences, University of Leeds , Leeds , UK ;
authors.forename: John S
authors.initials: JS
authors.lastname: Kane
authors.affiliation: a Leeds Gastroenterology Institute, St. James's University Hospital , Leeds , UK ;|b Leeds Institute of Biomedical and Clinical Sciences, University of Leeds , Leeds , UK ;
authors.forename: Ruchit
authors.initials: R
authors.lastname: Sood
authors.affiliation: c Division of Biostatistics , Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds , Leeds , UK ;
authors.forename: Graham R
authors.initials: GR
authors.lastname: Law
authors.affiliation: a Leeds Gastroenterology Institute, St. James's University Hospital , Leeds , UK ;|b Leeds Institute of Biomedical and Clinical Sciences, University of Leeds , Leeds , UK ;
authors.forename: David J
authors.initials: DJ
authors.lastname: Gracie
authors.affiliation: a Leeds Gastroenterology Institute, St. James's University Hospital , Leeds , UK ;|b Leeds Institute of Biomedical and Clinical Sciences, University of Leeds , Leeds , UK ;
authors.forename: Natalie
authors.initials: N
authors.lastname: To
authors.affiliation: d School of Medicine, University of Leeds , Leeds , UK.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Gold
authors.affiliation: a Leeds Gastroenterology Institute, St. James's University Hospital , Leeds , UK ;|b Leeds Institute of Biomedical and Clinical Sciences, University of Leeds , Leeds , UK ;
authors.forename: Alexander C
authors.initials: AC
authors.lastname: Ford
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D046728:Colitis, Microscopic / Q000145:classification / Q000175:diagnosis* / Q000473:pathology; D003106:Colon / Q000473:pathology*; D003113:Colonoscopy / Q000379:methods*; D003967:Diarrhea / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012044:Regression Analysis; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D006113:United Kingdom; D055815:Young Adult
keywords: Collagenous colitis; diarrhoea; irritable bowel syndrome; lymphocytic colitis; sensitivity; specificity