Hanauer 2004

Methods	Randomised, multi‐centre double‐blind, double‐dummy, controlled trial
Participants	CD patients before postoperative hospital discharge after ileocolic resection with a primary anastomosis for disease confined to the ileum and adjacent colon (N = 131) Patients were excluded if there was evidence of disease proximal or distal to the site of resection
Interventions	6‐mercaptopurine 50 mg/day for 24 months (n = 47) mesalamine 3 g/day for 24 months (n = 44) placebo for 24 months (n = 40)
Outcomes	Primary outcomes: clinical relapse (score of > 2 on the clinical recurrence grading scale) at 6, 12 and 24 months, radiographic relapse (a score of > 2 on the radiological recurrence grading scale) or endoscopic recurrence (score of > 2 on the Rutgeerts endoscopic scoring system) at 12 and 24 months Secondary outcome: adverse events
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer randomisation in blocks of 6
Allocation concealment (selection bias)	Low risk	Centralized pharmacy randomisation
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐blind Identical matching placebo
Incomplete outcome data (attrition bias) All outcomes	Low risk	Full data reported
Selective reporting (reporting bias)	Low risk	Appropriate data reported
Other bias	Low risk	None apparent