Background: There are multiple and controversial data about the relationship between Celiac Disease (CeD) and Inflammatory Bowel Disease (IBD).
We pretend to study the prevalence of CeD in patients diagnosed de novo of IBD in the area of Infanta Sofía University Hospital (a secondary center which serves more than 303,000 inhabitants in 53 municipalities in the northern area of the Autonomous Community of Madrid) between 2008 and 2012.
Methods: CeD screening was performed in newly diagnosed IBD patients by the determination of blood levels of IgA and IgA tissue transglutaminase antibodies (anti-tTG) (in case of IgA deficiency, IgA levels wth high sensitivity techniques or levels of IgG anti-tTG were determined). In those patients with positive anti-tTG, an endoscopic duodenal biopsy and a genetic test of CeD susceptibility (HQ DQ2/ DQ8 heterodimers) were performed.
None of the patients had received steroids or immunosuppressive or biological drugs in the three months prior to endoscopy. Celiac disease was diagnosed in patients with positive anti-tTG, a compatible duodenal biopsy, and good response to a gluten-free diet.
The prevalence of celiac disease in our group was compared with the expected prevalence in the general population according to published adult series of national studies.
Results: CeD screening was performed in 163 patients with de novo IBD: 65 with Crohn's disease (CD), 92 with Ulcerative Colitis (UC) and 6 with Unclassified Colitis (UnC). Six patients have positive anti-tTG (3.7%), 2 patients with CD (1 with colonic CD and 1 with ileocolonic CD) and 4 patients with UC (2 with ulcerative proctitis and 2 with extensive colitis), with no statistically significant differences between groups (p=0.999). 5/6 patients with positive anti-tTG were female and 1 patient was male; 5/6 were Caucasian, 1/6 was Hispanic. 5/6 patients with positive anti-tTG have positive CeD genetic test (2 with CD, 3 with UC). Duodenal biopsy was normal in 2 patients, and 4/6 presented histological results compatible with CeD (3 patients with UC and 1 with CD).
In all patients with CeD and IBD, IgA was in a normal range, anti-tTG were positive, and all of them had positive CeD genetic markers, and none of them had family history of CeD.
The prevalence of CeD in our group of patients with IBD is 2.45% (4/163 patients), 3 with UC and 1 with CD.
Conclusions: In our group of patients with de novo IBD, the prevalence of CeD is higher than the prevalence in the general adult population in Spain (expected prevalence about 1:370–1:389) and higher than the prevalence in our region (1:222–1:370 between adults). Therefore, it seems advisable to perform CeD screening in newly diagnosed IBD patients, especially in patients with UC or with CD with colon involvement.