Diagnostic Value of Quantitative Fecal Immunochemical Test (qFIT) and Calprotectin (FC) Dynamic Changes at 2 Weeks for Predicting 52-Week Relapse or Treatment Escalation in Biologic-Naive Ulcerative Colitis: A Multicenter, Prospective Cohort Study (DYNAMIC-UC)
This multicenter prospective cohort study aims to evaluate whether a \>50% decrease or normalization of both quantitative fecal immunochemical test (qFIT) and fecal calprotectin (FC) levels at 2 weeks after starting conventional therapy (mesalazine or corticosteroids) can predict clinical relapse or need for biologic/JAK inhibitor therapy escalation by 52 weeks in biologic-naive patients with active ulcerative colitis (UC). Secondary objectives include assessing predictive value at 4 weeks, building dynamic prediction models, conducting health economic evaluation (Number Needed to Test, NNT), and exploring baseline predictors of early biomarker response. Patients will be observed during standard care with stool samples collected at Weeks 0, 2, and 4. Biomarker results will be blinded to clinicians/patients until study completion.
• Age 18-75 years.
• Established diagnosis of Ulcerative Colitis (UC) confirmed by clinical, endoscopic, and histopathological criteria.
• Endoscopic disease activity (Mayo Endoscopic Subscore ≥ 2) confirmed by colonoscopy during screening.
• Biologic-naive (no prior exposure to any biologic agent \[e.g., infliximab, adalimumab, vedolizumab, ustekinumab\] or JAK inhibitor).
• No use of systemic corticosteroids (oral or intravenous) within 4 weeks prior to Baseline (Week 0) visit.
• If using oral or rectal mesalazine/5-ASA preparations, dose must have been stable for ≥2 weeks prior to Baseline (Week 0).
⁃ Willing and able to provide written informed consent.