"RUN-CD" is an investigator initiated "Non interventional Trial" on biologics in Crohn´s Disease (CD) patients in Germany with a prospective documentation of effectiveness in induction and maintenance therapy of biologics, especially of Ustekinumab, with a special interest on predictors of long-term responses and favorable disease outcome and documentation of severe side effects caused by the therapy with biologics.

The effectiveness and safety of induction and maintenance therapy of Ustekinumab and other biologics will be assessed in different relevant subgroups of Crohn's Disease patients. To this end, different confounders have to be considered. Patients followed-up for several years will likely receive changing treatments. These changes have to be taken into account. Furthermore, the decision to prescribe, to stop or to continue a treatment depends on the availability of treatment options and experiences with these alternatives:

1. Confounding by indication will be taken into account
2. Patient characteristics which likely influence the risk of developing a particular endpoint will be taken into account
3. The possible influence of co-medication will be considered
4. Changing risks over time will be considered
5. Power considerations needs to be conducted prior to the comparison of incidence rates
6. Appropriate statistical methods will be applied to deal with these challenges

The principles described above will be followed in a similar manner for the analysis of effectiveness and safety endpoints. An appropriate power analysis will be performed before each sub-analysis.

Inclusion Criteria:

CD-patients aged 18-80 years at enrollment written informed consent is given

Exclusion Criteria:

planned surgical intervention malignant disease in history lack of adequate documentation possibilities

The Crohn´s Disease (CD)-patients will be prospectively documented in the post-marketing observational investigator initiated study (RUN-CD). The diagnosis is made in accordance with current DGVS/ECCO CD-guidelines.