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Original article
Reproducibility of histological assessments of disease activity in UC
  1. Mahmoud H Mosli1,2,3,4,
  2. Brian G Feagan1,2,5,
  3. Guangyong Zou1,5,
  4. William J Sandborn1,6,
  5. Geert D'Haens1,7,
  6. Reena Khanna1,2,
  7. Cynthia Behling8,
  8. Keith Kaplan9,
  9. David K Driman10,
  10. Lisa M Shackelton1,
  11. Kenneth A Baker1,
  12. John K MacDonald1,
  13. Margaret K Vandervoort1,
  14. Mark A Samaan1,
  15. Karel Geboes11,
  16. Mark A Valasek12,
  17. Rish Pai13,
  18. Cord Langner14,
  19. Robert Riddell15,
  20. Noam Harpaz16,
  21. Maida Sewitch17,
  22. Michael Peterson18,
  23. Larry W Stitt5,
  24. Barrett G Levesque1,6
  1. 1Robarts Clinical Trials, Robarts Research Institute, Western University, London, Ontario, Canada
  2. 2Department of Medicine, Western University, London, Ontario, Canada
  3. 3Department of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
  4. 4Department of Epidemiology, Biostatistics and Occupational Medicine, McGill University, Montreal, Canada
  5. 5Department of Epidemiology and Biostatistics, Western University, London, Ontario, Canada
  6. 6Division of Gastroenterology, University of California San Diego, La Jolla, California, USA
  7. 7Department of Gastroenterology, Academic Medical Center, Amsterdam, The Netherlands
  8. 8Pacific Rim Pathology Medical Corporation, San Diego, California, USA
  9. 9Carolinas Medical Center, Charlotte, North Carolina, USA
  10. 10Department of Pathology, Western University, London, Ontario, Canada
  11. 11Department of Pathology, University Hospital of KU Leuven and UZ Gent, Leuven, Belgium
  12. 12Department of Pathology, University of California, San Diego, California, USA
  13. 13Department of Anatomic Pathology, Cleveland Clinic, Cleveland, Ohio, USA
  14. 14Department of Pathology, Medical University of Graz, Graz, Austria
  15. 15Department of Pathology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
  16. 16Department of Pathology, Mount Sinai Hospital, New York, New York, USA
  17. 17Department of Medicine, McGill University, Montreal, Quebec, Canada
  18. 18Department of Pathology, Western Washington Pathology and Multicare Health System, Tacoma, Washington, USA
  1. Correspondence to Dr Barrett G Levesque, Division of Gastroenterology, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA; bglevesque{at}ucsd.edu

Abstract

Objective Histopathology is potentially an important outcome measure in UC. Multiple histological disease activity (HA) indices, including the Geboes score (GS) and modified Riley score (MRS), have been developed; however, the operating properties of these instruments are not clearly defined. We assessed the reproducibility of existing measures of HA.

Design Five experienced pathologists with GI pathology fellowship training and expertise in IBD evaluated, on three separate occasions at least two weeks apart, 49 UC colon biopsies and scored the GS, MRS and a global rating of histological severity using a 100 mm visual analogue scale (VAS). The reproducibility of each grading system and for individual instrument items was quantified by estimates of intraclass correlation coefficients (ICCs) based on two-way random effects models. Uncertainty of estimates was quantified by 95% two-sided CIs obtained using the non-parametric cluster bootstrap method. Biopsies responsible for the greatest disagreement based on the ICC estimates were identified. A consensus process was used to determine the most common sources of measurement disagreement. Recommendations for minimising disagreement were subsequently generated.

Results Intrarater ICCs (95% CIs) for the total GS, MRS and VAS scores were 0.82 (0.73 to 0.88), 0.71 (0.63 to 0.80) and 0.79 (0.72 to 0.85), respectively. Corresponding inter-rater ICCs were substantially lower: 0.56 (0.39 to 0.67), 0.48 (0.35 to 0.66) and 0.61 (0.47 to 0.72). Correlation between the GS and VAS was 0.62 and between the MRS and VAS was 0.61.

Conclusions Although ‘substantial’ to ‘almost perfect’ ICCs for intrarater agreement were found in the assessment of HA in UC, ICCs for inter-rater agreement were considerably lower. According to the consensus process results, standardisation of item definitions and modification of the existing indices is required to create an optimal UC histological instrument.

  • CHRONIC ULCERATIVE COLITIS
  • IBD
  • INFLAMMATORY BOWEL DISEASE
  • CLINICAL TRIALS

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