Occurrence of demyelinating diseases after anti-TNFα treatment of inflammatory bowel disease: A Danish Crohn Colitis Database study

Introduction: It remains uncertain whether patients with inflammatory bowel disease (IBD) are at increased risk of developing demyelinating diseases, primarily multiple sclerosis (MS) and whether the introduction of biologic drugs in the treatment of IBD has altered this risk. Aim and methods: The aim was to conduct a systematic review of literature on occurrence of demyelinating diseases in IBD patients, to assess a national Danish anti-TNF alpha treated IBD cohort in order to search for and describe the IBD cases with coexisting demyelinating diseases, and finally to compare the occurrence of MS in the anti-TNF alpha cohort to the occurrence in the general Danish population. A systematic MEDLINE literature search was conducted, medical files were scrutinized for identification and description of cohort patients with demyelinating disease, and risk of MS was calculated as a standardized morbidity ratio (SMR) using general population data for comparison. Results: Four studies on the risk of demyelinating diseases in IBD were identified. One study revealed an observed prevalence of MS at onset of IBD at 3.7 times the expected (95% CI, 0.8-10.8). In the Danish anti-TNF alpha IBD cohort, 4 out of 651 patients developed demyelinating disorders after anti-TNF alpha treatment. The SMR for developing MS among Danish IBD patients treated with anti-TNF alpha was 4.2 (95% CI, 0.1-23.0). Conclusion: The literature review revealed an up to four-fold increased risk of demyelinating diseases, in particular MS, in IBD patients in general. The risk of developing MS in the anti-TNF alpha treated Danish cohort did apparently not exceed this risk. (C) 2008 European Crohn's and Colitis Organisation. Published by Elsevier B.V. All rights reserved.