Epidemiological investigation of different types of Crohn's disease patients undergoing first abdominal surgery in the era of biological agents: a population-based cohort study.

Background: Before the era of biological agents, most Crohn's disease patients required at least one intestinal resection surgery after diagnosis. However, clinical data regarding the abdominal surgery rates for Crohn's disease patients in the era of biological agents is not yet fully clear and needs to be updated.

Materials and methods: We retrospectively collected clinical data from 1115 Crohn's disease patients diagnosed and treated medically at The Second Xiangya Hospital of Central South University from January 2016 to January 2024. Using abdominal intestinal resection surgery as a clinical outcome, propensity score matching was employed to eliminate confounding factors. We explored the timing and proportion of abdominal surgery in patients with different Montreal classifications of Crohn's disease during the natural course of the disease, as well as the impact of the duration of the natural course and the use of biological agents on surgical outcomes.

Results: Montreal classification type B had the greatest impact on Crohn's disease surgery, especially with a higher proportion of type B3 patients undergoing surgery. Type A1 Crohn's disease patients underwent surgery earlier than types A2 and A3. The occurrence of behavior changes (B Change) during the natural course of the disease is a poor prognostic signal, indicating a significantly increased likelihood of surgery. The duration of the natural course from the onset of gastrointestinal symptoms to diagnosis and clinical observation outcomes did not directly affect the likelihood of surgery in Crohn's disease patients. Compared with Crohn's disease patients who did not receive biological agents, the surgery rate was significantly lower in patients who used biological agents. Additionally, Crohn's disease patients who received biological agents within 1 month of diagnosis had a significantly lower likelihood of undergoing surgical intervention. Moreover, Crohn's disease patients who received biological agent treatment within 19 months of the onset of gastrointestinal symptoms also had a significantly lower likelihood of undergoing surgery than other Crohn's disease patients.

Conclusions: In the era of biological agents, the risk of surgical intervention varies among Crohn's disease patients with different Montreal classifications, particularly when there is type B3 disease or a B Change. Clinicians should pay closer attention to surgical indications in such cases. For Crohn's disease patients, shortening the natural course before diagnosis and early use of biological agents after diagnosis can significantly reduce the risk of abdominal surgery.