Comparison 3. Initiation of prophylactic therapy guided by colonoscopic surveillance versus initiation of prophylactic therapy immediately after surgery.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
3.1 Randomised trial (102 weeks of follow‐up)	1		Risk Ratio (IV, Random, 95% CI)	Totals not selected
3.1.1 Clinical recurrence (CDAI >150) until week 102	1		Risk Ratio (IV, Random, 95% CI)	Totals not selected
3.1.2 Endoscopic recurrence (Rutgeerts' score ≥i2) at week 102	1		Risk Ratio (IV, Random, 95% CI)	Totals not selected
3.1.3 Endoscopic recurrence (Rutgeerts' score ≥i3) at week 102	1		Risk Ratio (IV, Random, 95% CI)	Totals not selected
3.1.4 Adverse events at 102 weeks	1		Risk Ratio (IV, Random, 95% CI)	Totals not selected
3.2 Cohort studies	2		Risk Ratio (IV, Random, 95% CI)	Totals not selected
3.2.1 Clinical recurrence (32 months of median follow‐up)	1		Risk Ratio (IV, Random, 95% CI)	Totals not selected
3.2.2 Surgical recurrence (50 months of median follow‐up)	1		Risk Ratio (IV, Random, 95% CI)	Totals not selected
3.2.3 Azathioprine withdrawal due to adverse event (50 months of median follow‐up)	1		Risk Ratio (IV, Random, 95% CI)	Totals not selected