ustekinumab (UST) can effectively induce and maintain clinical remission and mucosal healing of Crohn's disease (CD), but some patients still have poor response. Dose optimization is an effective way to improve the response rate of UST, and re-intravenous induction is a common way of optimization. For patients with secondary loss of response, about half of the patients can re-respond after dose optimization. We plan to use CDST-UST to stratify the response level of patients before treatment, select patients with poor response, and initially give multiple intravenous therapy as an intensive induction therapy strategy, so as to improve the response rate of these patients and achieve individualized treatment.

Inclusion Criteria:

• Diagnosed with CD;
• Active period; Age 18-75 years old;
• UST-CDST scores were used to treat patients with moderate and low responsive activity

Exclusion Criteria:

• Subjects had undergone extensive colectomy, subtotal colectomy, or total colectomy; The subject currently has ileostomy and colostomy; Patients with significant liver, kidney, endocrine, respiratory, neurological or cardiovascular diseases; Patients with fibrous stenosis and prestenosis dilatation; Contraindications of UST as documented in other specifications.