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Research Letter
December 2015

Risk of Demyelinating Diseases in the Central Nervous System in Patients With Inflammatory Bowel Disease Treated With Tumor Necrosis Factor Inhibitors

Author Affiliations
  • 1Department of Epidemiology Research, Statens Serum Institut, 2300 Copenhagen S, Denmark
JAMA Intern Med. 2015;175(12):1990-1992. doi:10.1001/jamainternmed.2015.5396

An association between usage of tumor necrosis factor inhibitors (anti-TNF) in patients with inflammatory bowel disease (IBD) and other immune-mediated diseases and demyelinating diseases in the central nervous system has been suggested by case reports.1,2 However, it remains uncertain whether these cases are directly related to anti-TNF therapy because there is evidence of an underlying association between demyelinating disease and IBD.3 In a nationwide population-based cohort, we compared rates of central demyelinating diseases among patients with IBD exposed and unexposed to anti-TNF.

The general study design and data sources used have been described in detail elsewhere.4,5 Briefly, using the Danish Civil Registration System, we identified a source population of 4 million people living in Denmark from January 1, 1999, to December 31, 2012. Unique personal identifiers permitted linkage to data from health registries on IBD diagnoses, anti-TNF exposure, and outcomes. After the date of first anti-TNF dose, the patient was categorized as ever exposed. The outcome was defined as a diagnosis of a central demyelinating disease, including multiple sclerosis, optic neuritis, transverse myelitis, and other central demyelinating diseases. Patients with a history of central demyelinating disease and those with use of anti-TNF prior to 1999 or prior to IBD diagnosis were excluded. The study was approved by the Danish Data Protection Agency. Ethics approval is not required for registry-based research in Denmark.