Ustekinumab Real World Evidence Study

The purpose of this study is to capture the real-world experience of CD patients treated with ustekinumab as part of their clinical care in a variety of care settings from large teaching/research centres to smaller district hospitals.

Inclusion Criteria: * Participants being given ustekinumab as part of their routine clinical care * Any of the following clinical indications: * CRP of 5mg/L or higher within three months prior to baseline * Faecal calprotectin of 250mg/L or higher within three months prior to baseline * Active disease on endoscopy within 6 months prior to baseline * Switching to ustekinumab because of an AE on another treatment * Post-operative prophylaxis * Age 18 or over * Able to give informed consent * Able to read English Exclusion Criteria: * Patient is, in the opinion of the investigator, not suitable to participate in the study * Use of ustekinumab outside of UK SmPC * Currently enrolled in an IMP/interventional study * Has received ustekinumab previously