Sood 2003.

Methods	Randomized controlled trial open label, active comparison (sulfasalazine) Induction period included (steroid tapering) Study duration 18 months
Participants	Newly diagnosed ulcerative colitis, severely active (SEO > 220) n = 25
Interventions	Azathioprine 2.5 mg/kg/day for 18 months Compared to sulfasalazine 6 g/day Co‐medication induction period: prednisolone 1 mg/kg/day; Taper off by 10 mg/day every fortnight until 20 mg/day, then 5 mg/day every 2 weeks Co‐medication maintenance: not reported
Outcomes	Main: maintenance of remission (after successful induction) for 18 months Treatment failure within 18 months Secondary: Failure to attain remission in induction phase Course of mean activity index Adverse events
Notes	The author was approached for clarification of the randomization and allocation concealment; no response was received
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "generating pseudo‐random numbers ranging from 0‐1 using a scientific calculator"
Allocation concealment (selection bias)	Unclear risk	Unclear, not described in the published study
Blinding of outcome assessment (detection bias) All outcomes	High risk	Quote: "open‐label"
Incomplete outcome data (attrition bias) All outcomes	Low risk	Two withdrawals due to side effects
Selective reporting (reporting bias)	Unclear risk	All outcomes reported, except endoscopic evaluation
Other bias	Low risk	Nothing of note