A Study to Assess the Long-Term Safety of Ustekinumab Versus Other Biologics in Patients With Crohn's Disease and Ulcerative Colitis

This is an observational study — no new treatment is given — that tracks real-world safety outcomes in people with Crohn's disease or ulcerative colitis who are starting a biologic medication. It compares the long-term safety of ustekinumab (Stelara) against other biologic drugs using military health records. **You may be eligible if...** - You are 18 or older - You have a confirmed diagnosis of Crohn's disease or ulcerative colitis - You are newly starting ustekinumab or a comparable biologic medication - You have at least one year of health records in the military's electronic health record system prior to starting the medication **You may NOT be eligible if...** - You are under 18 at the time of starting the medication - You do not have a confirmed diagnosis of Crohn's disease or ulcerative colitis - You have a history of HIV, organ transplant, or cancer (other than non-melanoma skin cancer) - You have been diagnosed with rheumatoid arthritis, ankylosing spondylitis, or psoriatic arthritis within the past year Talk to your doctor to see if this trial is right for you.