title: Comparing disease activity indices in ulcerative colitis.
abstract: BACKGROUND
  Comparisons between disease activity indices for ulcerative colitis (UC) are few. This study evaluates three indices, to determine the potential impact of inter-observer variation on clinical trial recruitment or outcome as well as their clinical relevance.
  
  
  METHODS
  One hundred patients with UC were prospectively evaluated, each by four specialists, followed by videosigmoidoscopy, which was later scored by each specialist. The Simple Clinical Colitis Activity (SCCAI), Mayo Clinic and Seo indices were compared by assigning a disease activity category from published thresholds for remission, mild, moderate and severe activity. Inter-observer variation was evaluated using Kappa statistics and its effect for each patient on recruitment and outcome measures for representative clinical trials calculated. Clinical relevance was assessed by comparing an independently assigned clinical category, taking all information into account as if in clinic, with the disease activity assigned by the indices.
  
  
  RESULTS
  Inter-observer agreement for SCCAI (κ=0.75, 95% CI 0.70-0.81), Mayo Clinic (κ=0.72, 95% CI 0.67-0.78) and Seo (κ=0.89, 95% CI 0.83-0.95) indices was good or very good as was the agreement for rectal bleeding (κ=0.77) and stool frequency (κ=0.90). Endoscopy in the Mayo Clinic index had the greatest variation (κ=0.38). Inter-observer variation alone would have excluded up to 1 in 5 patients from recruitment or remission criteria in representative trials. Categorisation by the SCCAI, Mayo Clinic and Seo indices agreed with the independently assigned clinical category in 61%, 67% and 47% of cases respectively.
  
  
  CONCLUSIONS
  Trial recruitment and outcome measures are affected by inter-observer variation in UC activity indices, and endoscopic scoring was the component most susceptible to variation.
authors.affiliation: Currently at Department of Gastroenterology, St Vincent's Hospital, Sydney, Australia.
authors.forename: A J
authors.initials: AJ
authors.lastname: Walsh
authors.affiliation: Medical Sciences Division, University of Oxford, Oxford, UK.
authors.forename: A
authors.initials: A
authors.lastname: Ghosh
authors.affiliation: Translational Gastroenterology Unit, John Radcliffe Hospital, Oxford, UK.
authors.forename: A O
authors.initials: AO
authors.lastname: Brain
authors.affiliation: Currently at Department of Surgery, Universitas Hospital, University of the Free State, Bloemfontein, South Africa.
authors.forename: O
authors.initials: O
authors.lastname: Buchel
authors.affiliation: Currently at Department of Gastroenterology, Princess Alexandra Hospital, Brisbane, Australia.
authors.forename: D
authors.initials: D
authors.lastname: Burger
authors.affiliation: Currently at Department of Biomedical Sciences, University of Sheffield, Sheffield, UK.
authors.forename: S
authors.initials: S
authors.lastname: Thomas
authors.affiliation: Translational Gastroenterology Unit, John Radcliffe Hospital, Oxford, UK.
authors.forename: L
authors.initials: L
authors.lastname: White
authors.affiliation: Centre for Statistics in Medicine, University of Oxford, Oxford, UK.
authors.forename: G S
authors.initials: GS
authors.lastname: Collins
authors.affiliation: Translational Gastroenterology Unit, John Radcliffe Hospital, Oxford, UK.
authors.forename: S
authors.initials: S
authors.lastname: Keshav
authors.affiliation: Translational Gastroenterology Unit, John Radcliffe Hospital, Oxford, UK. Electronic address: simon.travis@ndm.ox.ac.uk.
authors.forename: S P L
authors.initials: SP
authors.lastname: Travis
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003093:Colitis, Ulcerative / Q000145:classification / Q000175:diagnosis / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011446:Prospective Studies; D012720:Severity of Illness Index; D012812:Sigmoidoscopy; D055815:Young Adult
keywords: Activity index; Clinical trial design; Endoscopy; Mayo Clinic index; Ulcerative colitis