Immunosenescence Phenotypes and Net Clinical Benefit of Advanced Therapies in Older Adults With Inflammatory Bowel Disease: A Prospective Multicenter Observational Cohort Study

The goal of this observational study is to learn whether signs of immune aging and frailty can help predict the balance of benefits and risks of advanced therapies in adults aged 60 years or older with inflammatory bowel disease (IBD) who are starting a new advanced therapy. Treatment will be chosen by the participant's usual clinical team and will not be assigned by the study. The main questions it aims to answer are: Are baseline immune-aging and frailty characteristics associated with net clinical benefit at 52 weeks, defined as steroid-free clinical remission without serious infection, treatment discontinuation because of adverse events, IBD-related hospitalization, or IBD-related surgery? Can a low-cost combination of clinical and laboratory markers help identify older adults with IBD who are more likely to have favorable or unfavorable outcomes after starting advanced therapy? Participants will: Continue the advanced therapy selected as part of their usual clinical care. Complete study assessments of frailty, nutritional status, disease activity, and other health factors. Have routine and study-related blood tests, including measures related to immune aging such as CD4/CD8 ratio and interleukin-6 (IL-6). Be followed at approximately baseline, weeks 6, 14, 26, and 52, with longer-term safety follow-up planned to week 104 when feasible. Have information collected on remission, infections, hospitalizations, surgery, treatment continuation or change, and other health outcomes.