IBDSL Biobank Project. Molecular Markers for Diagnosis and Therapy Response in IBD. A Prospective Population Based Biobank of Inflammatory Bowel Disease Patients in Zuid Limburg, The Netherlands.

Background: Inflammatory Bowel Disease (IBD), encompassing Crohn's Disease (CD) and Ulcerative Colitis (UC), is a chronic disabling condition of the intestine. Most patients experience sequences of exacerbation in which quality of life is often impaired. Also society endures heavily, as IBD healthcare costs are estimated at 4.6-5.6 billion euros per year and high rates of unemployment and work disability are reported. The current incidence estimate is 256.000 Europeans per year, and yet increases.

IBD arises from complex interactions between a genetically altered intestinal immune response, environmental factors and intestinal microbiota. Disease phenotypes are heterogeneous and predicting individual disease course or therapy response is still merely possible; treatment of choice for instance remains a trial-and-error based succession of regimens. Further exploration of the underlying biologic mechanisms, and the identification and validation of non-invasive markers to predict disease course and therapy response are the foremost challenges in IBD field at this moment.

Deeply phenotyped IBD cohorts with a biobank are ideal tools for this type of research, and are warranted. Most IBD biobanks reflect hospital based populations thereby over representing severe and therapy refractory patients. However, many hypotheses require designs with a full IBD spectrum. Secondly, phenotypes are mostly ascertained retrospectively, which makes results prone for bias. As no prospective population based biobank excists, we started the population based IBD South Limburg (IBDSL) biobank project.

IBDSL: The IBDSL project was first established in 1991, when gastroenterologists started prospectively registering all IBD patients residing in South Limburg, the Netherlands. As from 2011, this cohort is being scaled up into a biobank and focus expanded from epidemiology towards exploring underlying biologic mechanisms and identifying markers to predict disease course or therapy response.

Population: Every adult IBD patient, diagnosed in South Limburg after 1991 and permanently residing in South Limburg (the Netherlands), is eligible to participate. The population based nature was reached via a multi-faceted approach; incident cases were prospectively identified through the participating hospitals, and missed patients were retrospectively identified using the nationwide histopathology registry. In 2011, over 3500 patients were included, representing >93% of the IBD population in South Limburg. Adults and partners of included patients serve as controls.