Levine 2002.

Study characteristics
Methods	Multicenter, randomized, double‐blind, double‐dummy, dose‐response, parallel‐group study
Participants	Adults (aged 18 to 80 years) with mild to moderately‐active ulcerative colitis confirmed by flexible sigmoidoscopy (N = 154)
Interventions	Balsalazide 6.75 g/day (n = 35), Balsalazide 2.25 g/day (n = 35) or Asacol 2.4 g/day (n = 36) for 8 weeks
Outcomes	Primary outcome: Difference between treatment groups in rectal bleeding and in at least one other symptom. Improvement was defined as improvement in at least one category of the disease activity scale (i.e. normal, mild, moderate, severe) Secondary outcomes: Remission status (normal stool frequency and no blood in stool for 48 hours before visit, physician’s global assessment score of quiescent and a sigmoidoscopy score of mild or normal), rectal biopsy score, and IBDQ score
Notes	For the purposes of this review we used only the comparison between Balsalazide 6.75 g and Asacol 2.4 g (i.e. equimolar doses) Funding support and conflicts of interest were not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described
Allocation concealment (selection bias)	Unclear risk	Not described
Blinding (performance bias and detection bias) All outcomes	Low risk	Double‐blind, double‐dummy: Placebos were identical in appearance to the Balsalazide capsules and mesalamine (Asacol) tablets
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	31% dropout rate. Dropouts appear to be balanced across intervention groups. More participants withdrew from the low‐dose Balsalazide and mesalamine groups due to lack of therapeutic effect than the high‐dose Balsalazide group
Selective reporting (reporting bias)	Low risk	Expected outcomes were reported
Other bias	Low risk	The study appears to be free of other sources of bias