Inflammatory Bowel Disease and the Risk of Autoimmune Diseases

An increased risk of autoimmune disease has been reported in patients with inflammatory bowel disease [IBD]. Using data from the Clinical Practice Research Datalink [CPRD], this study set out to further examine this relationship.

Patients with a first-time IBD diagnosis were randomly matched to an equal-sized IBD-free comparison group. Incidence rates for new-onset autoimmune diseases were estimated. A nested case-control analysis comprising IBD patients was conducted, using conditional logistic regression to assess whether IBD severity, duration, or treatment influences the risk of developing autoimmune diseases.

During follow-up, 1069 IBD and 585 IBD-free patients developed an incident autoimmune disease. An increased incidence of autoimmune disease was observed in IBD patients (incidence rate [IR] 9.65, 95% confidence interval [CI] 9.09-10.24) compared with the non-IBD comparison group [IR 5.22, 95% CI 4.82-5.66]. In IBD patients, increased disease severity was associated with an increased risk of autoimmune disease development (odds ratio [OR] 1.62, 95% CI 1.28-2.05). Current antibiotic use was also associated with an increased risk [adjusted OR 1.72, 95% CI 1.07-2.78]. A reduced risk of incident autoimmune diseases was observed for current long-term users of aminosalicylates [adjusted OR 0.72, 95% CI 0.57-0.91].

Individuals with IBD had an increased risk of developing an autoimmune disease. Increased disease severity and current antibiotic use were associated with an increased relative risk of developing additional autoimmune diseases in IBD patients. Long-term current aminosalicylate use was associated with a reduced risk.