Ulcerative colitis (UC) is an incurable, immune-mediated inflammatory disease of the large bowel that typically requires long term immunosuppressive drugs to induce and maintain remission. Hospitalisation due to severe, uncontrolled disease is a common occurrence and estimated to affect up to 25% of UC patients. Janus kinase inhibitors (JAKi) have attracted considerable attention as potential candidates for treating hospitalised patients with severe UC and are increasingly used in this setting. For tofacitinib, there are accumulating data supporting their use as effective induction agents to prevent colectomy and reduce length of hospitalisation, however, these are limited to small case series and small cohort studies only. There are no published data for the use of filgotinib and upadacitinib for treating severe inpatient colitis.

The aim of this study is to develop a large retrospective cohort of JAKi-treated hospitalised UC patients to describe the safety and effectiveness of using JAKi in this setting.

Inclusion Criteria:

• Patient ≥ 18 years old,
• Established diagnosis of ulcerative colitis as per ECCO (European Crohn´s and Colitis Organisation) criteria,
• Hospitalisation at any point for treatment of ulcerative colitis disease relapse,
• Receiving at least one dose of tofacitinib, filgotinib, or upadacitinib for the treatment of severe UC during inpatient stay,
• Endoscopically confirmed active disease (Mayo endoscopic subscore ≥ 2) within previous four weeks,
• Patient who has received full information about the organization of the research and who has not objected to his or her participation and to the use of his or her data.

Exclusion Criteria:

• Diagnosis of Crohn's disease or unclassified Inflammatory Bowel Disease,
• Receiving JAKi prior to admission,
• Clostridium difficile, cytomegalovirus (CMV), or other enteric infections identified on admission.

Patients hospitalized for ulcerative colitis disease relapse and treated during their stay with JAKi (tofacitinib, filgotinib, or upadacitinib) between 01/01/2019 and 01/12/2023.