The loss of response rate of ustekinumab(UST) is high, and the specific mechanism has not yet been elucidated. Our study aimed to retrospectively analyze the clinical efficacy and influence factors of individualized treatment of ustekinumab (UST) in patients with Crohn's disease (CD).

Interleukin (IL-12) and interleukin (IL-23) co-contain the P40 subunit, and ustekinumab (UST) is a fully humanized IgG1 monoclonal antibody that targets the P40 subunit. The conventional regimen of UST in the treatment of Crohn's disease is that after the first sufficient dose (6 mg/kg) of intravenous infusion, 90 mg UST is injected subcutaneously at the 8th week according to the patient's response, and maintenance therapy is given every 8 or 12 weeks. However, data from real-world studies suggest that the clinical efficacy of treating CD with the conventional UST regimen is less than ideal.Our study aimed to retrospectively analyze the clinical efficacy and influence factors of individualized treatment of ustekinumab in patients with Crohn's disease .

Inclusion Criteria:

1. Diagnosed with moderate to severe Crohn's disease
2. Receiving treatment with ustekinumab

Exclusion Criteria:

1. Combined with other autoimmune diseases (such as systemic lupus erythematosus, Sjogren's syndrome, etc.), malignant tumors, or severe cardiovascular and cerebrovascular diseases
2. Merge active tuberculosis or severe infection
3. Liver and kidney dysfunction
4. Pregnancy or lactation period
5. Combination therapy with hormones, immunosuppressants, small molecule drugs, or other biological agents
6. Clinical data missing ≥ 30% or lost to follow-up during the follow-up period.

Inflammatory bowel disease (IBD) is a chronic inflammatory disease involving the digestive tract, including two clinical phenotypes: Crohn's disease (CD) and ulcerative colitis (UC).