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

BACKGROUND AND AIMS: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Development and validation of novel algorithms to identify patients with inflammatory bowel diseases in Israel: an epi-IIRN group study.

BACKGROUND: Before embarking on administrative research, validated case ascertainment algorithms must be developed. We aimed at developing algorithms for identifying inflammatory bowel disease (IBD) patients, date of disease onset, and IBD type (Crohn's disease [CD] vs ulcerative colitis [UC]) in the databases of the four Israeli Health Maintenance Organizations (HMOs) covering 98% of the population. METHODS: Algorithms were developed on 5,131 IBD patients and 2,072 controls, following independent chart review (60% CD and 39% UC). We reviewed 942 different combinations of clinical parameters aided by mathematical modeling. The algorithms were validated on an independent cohort of 160,000 random subjects. RESULTS: The combination of the following variables achieved the highest diagnostic accuracy: IBD-related codes, alone if more than five to six codes or combined with purchases of IBD-related medications (at least three purchases or ≥3 months from the first to last purchase) (sensitivity 89%, specificity 99%, positive predictive value [PPV] 92%, negative predictive value [NPV] 99%). A look-back period of 2-5 years (depending on the HMO) without IBD-related codes or medications best determined the date of diagnosis (sensitivity 83%, specificity 68%, PPV 82%, NPV 70%). IBD type was determined by the majority of CD/UC codes of the three recent contacts or the most recent when less than three contacts were recorded (sensitivity 92%, specificity 97%, PPV 97%, NPV 92%). Applying these algorithms, a total of 38,291 IBD patients were residing in Israel, corresponding to a prevalence rate of 459/100,000 (0.46%). CONCLUSION: The application of the validated algorithms to Israel's administrative databases will now create a large and accurate ongoing population-based cohort of IBD patients for future administrative studies.