John Marshall, MD, MSc, FRCPC, AGAF

Professor, Department of Medicine
Chief of Clinical Service for Gastroenterology, Hamilton Health Sciences


Clinical outcomes research 


Dr. Marshall conducts and contributes to clinical trials of novel therapy for inflammatory bowel disease including novel biologic agents and small molecules, and innovative applications of existing therapies such as denosumab and vitamin D. He is also evaluating novel approaches to delivering care for IBD including enhanced participation by advanced-practice nurses and the application of standardized metrics for quality of care. Dr. Marshall is also evaluating both the patient impact of IBD care transitions (such as from pediatric to adult care, and from hospital to ambulatory care), and the role of IBD nurse practitioners in facilitating such transitions. He continues to conduct systematic reviews of IBD therapy such as 5ASA and ulcerative colitis rescue agents. Dr. Marshall also leads development and dissemination of national and global clinical practice guidelines for IBD care. In addition to his research activities, Dr. Marshall currently serves as Editor-in-Chief of the Canadian Journal of Gastroenterology and Hepatology. He is Chief of Service for Gastroenterology at Hamilton Health Sciences, and Clinical Lead for the HHS IBD Clinic. He is heavily involved in postgraduate medical education, and is founder and chair of the CARE program held in conjunction with major international conferences in gastroenterology and hepatology.

  1. Marshall, JK, Bessette, L, Shear, NH, Lebovic, G, Glass, J, Millson, B et al.. Canada's Study of Adherence Outcomes in Patients Receiving Adalimumab: 3-year Results From the COMPANION Study. Clin Ther. 2018;40 (6):1024-1032. doi: 10.1016/j.clinthera.2018.04.017. PubMed PMID:29803532 .
  2. Marshall, JK, Bessette, L, Thorne, C, Shear, NH, Lebovic, G, Gerega, SK et al.. Impact of the Adalimumab Patient Support Program's Care Coach Calls on Persistence and Adherence in Canada: An Observational Retrospective Cohort Study. Clin Ther. 2018;40 (3):415-429.e6. doi: 10.1016/j.clinthera.2018.02.001. PubMed PMID:29519714 .
  3. Cho, R, Wickert, NM, Klassen, AF, Tsangaris, E, Marshall, JK, Brill, H et al.. Identifying Needs in Young Adults With Inflammatory Bowel Disease: A Qualitative Study. Gastroenterol Nurs. ;41 (1):19-28. doi: 10.1097/SGA.0000000000000288. PubMed PMID:29373352 .
  4. Carter, F, Alsayb, M, Marshall, JK, Yuan, Y. Mesalamine (5-ASA) for the prevention of recurrent diverticulitis. Cochrane Database Syst Rev. 2017;10 :CD009839. doi: 10.1002/14651858.CD009839.pub2. PubMed PMID:28973845 .
  5. Ghosh, S, Louis, E, Beaugerie, L, Bossuyt, P, Bouguen, G, Bourreille, A et al.. Development of the IBD Disk: A Visual Self-administered Tool for Assessing Disability in Inflammatory Bowel Diseases. Inflamm. Bowel Dis. 2017;23 (3):333-340. doi: 10.1097/MIB.0000000000001033. PubMed PMID:28146002 PubMed Central PMC5319390.
  6. Narula, N, Cooray, M, Anglin, R, Muqtadir, Z, Narula, A, Marshall, JK et al.. Impact of High-Dose Vitamin D3 Supplementation in Patients with Crohn's Disease in Remission: A Pilot Randomized Double-Blind Controlled Study. Dig. Dis. Sci. 2017;62 (2):448-455. doi: 10.1007/s10620-016-4396-7. PubMed PMID:27975236 .
  7. Fallone, CA, Gisbert, JP, Chiba, N, Veldhuyzen van Zanten, S, Fischbach, L, Hunt, RH et al.. Reply. Gastroenterology. 2017;152 (1):303-304. doi: 10.1053/j.gastro.2016.11.036. PubMed PMID:27893977 .
  8. Cheng, J, Iorio, A, Marcucci, M, Romanov, V, Pullenayegum, EM, Marshall, JK et al.. Bayesian approach to the assessment of the population-specific risk of inhibitors in hemophilia A patients: a case study. J Blood Med. 2016;7 :239-253. doi: 10.2147/JBM.S103087. PubMed PMID:27822129 PubMed Central PMC5087814.
  9. Cheng, J, Pullenayegum, E, Marshall, JK, Iorio, A, Thabane, L. Impact of including or excluding both-armed zero-event studies on using standard meta-analysis methods for rare event outcome: a simulation study. BMJ Open. 2016;6 (8):e010983. doi: 10.1136/bmjopen-2015-010983. PubMed PMID:27531725 PubMed Central PMC5013416.
  10. Fallone, CA, Chiba, N, van Zanten, SV, Fischbach, L, Gisbert, JP, Hunt, RH et al.. The Toronto Consensus for the Treatment of Helicobacter pylori Infection in Adults. Gastroenterology. 2016;151 (1):51-69.e14. doi: 10.1053/j.gastro.2016.04.006. PubMed PMID:27102658 .
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