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World J Gastroenterol. Jul 14, 2008; 14(26): 4127-4130
Published online Jul 14, 2008. doi: 10.3748/wjg.14.4127
Use of the Crohn’s disease activity index in clinical trials of biological agents
Hugh James Freeman
Hugh James Freeman, Department of Medicine (Gastroen-terology), University of British Columbia, Vancouver, British Columbia V6T 1W5, Canada
Author contributions: Freeman HJ contributed all to this paper.
Correspondence to: Dr. Hugh Freeman, MD, Professor, Department of Medicine (Gastroenterology), University of British Columbia Hospital, 2211 Wesbrook Mall, Vancouver, British Columbia V6T 1W5, Canada. hugfree@shaw.ca
Telephone: +1-604-8227216
Fax: +1-604-8227236
Received: May 22, 2008
Revised: June 23, 2008
Accepted: June 30, 2008
Published online: July 14, 2008
Abstract

The Crohn’s disease activity index (CDAI) has been commonly used to assess the effects of treatment with different agents in Crohn’s disease (CD). However, these studies may be compromised, if the results compared to a placebo or standard therapy group (in the absence of a placebo) substantially differ from the expected response. In addition, significant concerns have been raised regarding the reliability and validity of the CDAI. Reproducibility of the CDAI may be limited as significant inter-observer error has been recorded, even if measurements are done by experienced clinicians with expertise in the diagnosis and treatment of CD. Finally, many CDAI endpoints are open to subjective interpretation and have the potential for manipulation. This is worrisome as there is the potential for significant financial gain, if the results of a clinical trial appear to provide a positive result. Physicians caring for patients should be concerned about the positive results in clinical trials that are sponsored by industry, even if the trials involve respected centers and the results appear in highly ranked medical journals.

Keywords: Crohn’s disease; Crohn’s disease activity index; Clinical trials; Infliximab; Adalimumab; Corticosteroids; Azathioprine