2.4. Follow-up and study endpoints
intestinal fistula
The date of initial surgery for patients with CD between September 2019 and September 2021 was used as the starting point of the study. The follow-up period was 90 days. Development of intestinal fistula within or at 90 days after surgery was used as the study endpoint. Follow-up was conducted by outpatient visits, telephone inquiries, or hospitalization.