title: Can endoscopy be avoided in the assessment of ulcerative colitis in clinical trials?
abstract: BACKGROUND
  There is no gold standard index in the measurement of ulcerative colitis (UC) disease activity in clinical trials. Mucosal healing has been described as an important clinical endpoint requiring endoscopic assessment, which is unpleasant for the patient and may hamper recruitment to trials. The aim of this study was to determine whether endoscopy is necessary in the assessment of UC disease activity and whether a noninvasive disease activity index (partial Mayo score) could be used to predict the Mayo score.
  
  
  METHODS
  In all, 149 subjects with moderate to severe UC enrolled in a clinical trial were assessed using total and partial Mayo scores. Histologic assessment of biopsies was performed. A regression model was constructed to predict total Mayo score from the partial Mayo score and histology score from the Mayo score. A Bland-Altman test of agreement was performed.
  
  
  RESULTS
  The partial Mayo score correlated closely with the total Mayo score at week 4 (rho = 0.97) and week 8 (rho = 0.98). The model to predict total from partial Mayo score showed excellent correlation (rho = 0.97) and good agreement with the total Mayo score at week 4 and the week 8 validation set (rho = 0.97) and accurately classified disease severity (kappa = 0.82). The model to predict histology score from the Mayo score correlated only moderately with the actual histology score at week 4 (rho = 0.59) and week 8 (rho = 0.36).
  
  
  CONCLUSIONS
  The Mayo score can be accurately predicted from the partial Mayo score. A noninvasive index can replace the Mayo score in future clinical trials.
authors.affiliation: School of Clinical Sciences, University of Bristol, Bristol, UK. Ashwin.Dhanda@bristol.ac.uk
authors.forename: Ashwin D
authors.initials: AD
authors.lastname: Dhanda
authors.forename: Tom J
authors.initials: TJ
authors.lastname: Creed
authors.forename: Rosemary
authors.initials: R
authors.lastname: Greenwood
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Sands
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Probert
mesh_terms: D003093:Colitis, Ulcerative / Q000175:diagnosis*; D006801:Humans; D012044:Regression Analysis; D012720:Severity of Illness Index; D012812:Sigmoidoscopy