The Association of Inflammatory Bowel Diseases with Autoimmune Disorders: A Report from the epi-IIRN

There are conflicting data on the association between inflammatory bowel diseases [IBD] and autoimmunity disorders. The aim of this study was to explore this association including the effect of medications.

We utilized health administrative data collected by three of the four health maintenance organizations [HMOs] in Israel, covering 52% of the country's population. We explored the prevalence of the following autoimmune disorders: insulin-dependent diabetes mellitus [IDDM], psoriasis, Sjögren syndrome, coeliac disease, systemic lupus erythematosus [SLE], primary sclerosis cholangitis [PSC] and autoimmune thyroiditis, among all IBD patients vs non-IBD controls. Case ascertainment was determined according to validated computerized algorithms.

In total, 12625 IBD patients were compared to 12625 controls. A total of 1395 [11.1%] IBD patients had at least one autoimmune disease compared with 740 [5.9%] of non-IBD controls (odds ratio [OR] = 1.99 [95% confidence interval 1.81-2.19]; p < 0.05); all autoimmune diseases, except for thyroiditis, were more prevalent among IBD patients. Adjusted for confounding variables, anti-tumour necrosis factor [anti-TNF] medications were associated with a higher prevalence of psoriasis (54 [5.7%] in IBD vs 177 [4.1%] in controls; OR = 1.50 [1.07-2.08]; p < 0.05) but lower prevalence of Sjögren (1 [0.1%] vs 39 [0.9%]; OR [95% CI] = 0.13 [0.02-0.94]; p < 0.05) and coeliac disease (11 [1.2%] vs 68 [1.6%]; OR [95% CI] = 0.51 [0.27-0.99]; p < 0.05). Thiopurines and 5-aminosalicylates were not associated with any autoimmune disorder.

IBD is associated with all autoimmune diseases explored here except for thyroiditis. Anti-TNF users have a higher prevalence of psoriasis, and lower prevalence of Sjögren and coeliac disease.