Oren 1997.

Methods	Randomized, double‐blind, placebo‐controlled, multi‐center trial
Participants	Chronic active Crohn's disease (HBI > 7), on steroids (> 7.5 mg/day; prednisone equivalent dose) and/or immunosuppressives for at least 4 months during the past year, no immunosuppressives 3 months prior to entry Unacceptable steroid side effects or failure to respond to high‐dose steroids were also considered reasons for inclusion (N = 84)
Interventions	Oral methotrexate (12.5 mg/wk, n = 26), 6‐mercaptopurine (50 mg/day, n = 32) or placebo (n = 26) for 9 months Prednisone and 5‐ASA were continued at the discretion of the physician
Outcomes	Remission (HBS < 3) and not receiving steroids Maintenance of remission in patients entering first remission up to the 9 month follow‐up Relapse was defined as a rise of 3 or more points on the HBI and/or a reintroduction of steroids at a dose of > 300 mg/month Decrease in steroid requirement General well being All data analysis was performed on an intention to treat basis
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	The manuscript does not describe the method used for randomization
Allocation concealment (selection bias)	Unclear risk	The manuscript does not describe methods used for allocation concealment
Blinding (performance bias and detection bias) All outcomes	Low risk	The investigators were blinded to treatment assignment An unblinded independent observer and the pharmacist were the only persons who had access to the drug key
Incomplete outcome data (attrition bias) All outcomes	Low risk	Dropouts and treatment failures were not significantly different between the three groups ITT analysis was used
Selective reporting (reporting bias)	Low risk	The published report included all expected outcomes
Other bias	Low risk	The study appears to be free of other sources of bias