This multicenter longitudinal observational cohort study aims to characterize objective disease-control trajectories, treatment adaptation, and long-term clinical outcomes among adults with ulcerative colitis receiving routine clinical care.
Longitudinal clinical information, laboratory biomarkers, endoscopic assessments, intestinal ultrasound when available, medication exposure, corticosteroid use, hospitalization, surgery, and other clinically relevant events will be integrated to reconstruct time-varying disease states.
The primary longitudinal construct is time under objective uncontrolled disease (TUOD), defined as the cumulative proportion of evaluable follow-up time during which objective evidence indicates inadequately controlled ulcerative colitis. Periods without sufficient information to determine objective inflammatory status will be classified separately as unknown or unobservable rather than assumed to represent disease control.
The study will also evaluate two prespecified treatment-strategy questions. First, among patients initiating advanced therapy, long-term outcomes will be compared according to the initial advanced-therapy strategy irrespective of subsequent treatment modification or switching. Second, among patients developing confirmed objective disease non-control during advanced therapy, outcomes associated with alternative treatment-adaptation strategies, including within-mechanism optimization and switching to an alternative therapeutic mechanism, will be evaluated.
The study is non-interventional. Treatment selection, treatment optimization, switching, diagnostic investigations, and follow-up are determined by treating physicians according to routine clinical practice and are not assigned by the study.