Individual Treatment of Ustekinumab in Perianal Fistulizing Crohn's Disease

Inclusion Criteria: * Clinical diagnosis of Perianal Fistulizing Crohn's Disease * Receive ustekinumab therapy Exclusion Criteria: * Ustekinumab combined with hormones, immunosuppressants, other biologics or small molecule drugs * Combined with other autoimmune diseases, such as systemic lupus erythematosus, rheumatoid arthritis, Graves disease, etc. * Combined with serious infectious diseases, such as active tuberculosis, EBV infection, cytomegalovirus infection, etc. * Combined with malignant tumor * Clinical data missing ≥30% or no follow-up