Selection and Efficacy-Influencing Factors of First-Line Biologic Agents in Moderate-to-Severe Ulcerative Colitis

Who May Qualify: - Age range of 18-70 years old, gender not limited; - According to international guidelines and consensus, patients with ulcerative colitis should be diagnosed to exclude radiation enteritis, infectious enteritis, tumor related diseases, etc; - Patients assessed as moderate to severe ulcerative colitis based on the Mayo score; - During the follow-up period, no relevant treatments (drugs and surgery) were used that could affect the assessment of the efficacy of biologics Who Should NOT Join This Trial: - Patients with hemodynamic instability; - Patients with obvious liver and kidney function injury: bilirubin, aminotransferase (ALT, AST) exceeded the upper limit of normal by 2 times; eGFR\<60ml/min or dialysis patients; - Patients allergic to IFX or VDZ; - Patients whose primary disease was gastrointestinal malignancy; - Patients currently suffering from serious or uncontrolled underlying diseases of the blood, digestive tract, metabolism, endocrine, lung, heart, nervous system, mental system, etc.; - Female patients during pregnancy and breastfeeding (including patients with reproductive needs); - Patients with current infection with infectious diseases (hepatitis B, hepatitis C, syphilis, AIDS, tuberculosis, etc.); - Patients who cannot cooperate with regular follow-up and review of laboratory indicators; - Any other circumstances which, in the opinion of the investigator, would render the subject unfit for study inclusion. Always talk to your doctor about whether this trial is right for you.