Willoughby 1988.

Study characteristics
Methods	Randomized, double‐dummy, multicenter comparison of SASP and Olsalazine
Participants	Out‐patients with mild to moderately‐active ulcerative colitis, either first attack or relapse (N = 56)
Interventions	Oral sulphasalazine, 3 g/day (n = 30), or oral olsalazine, 3 g/day (n = 26), each in divided doses. Dose escalation schedule was used for first week of treatment after which full‐dose therapy continued for further 4 weeks. Tablets were counted to monitor compliance
Outcomes	As well as diary cards, participants were clinically assessed upon entry, after 2 weeks, and after 5 weeks. Biopsy, sigmoidoscopy, and lab tests were performed at entry and after week 5 Clinical response was evaluated as changes in stool frequency and loss of blood and mucus from stools. Sigmoidoscopic and histological assessments were considered to have improved if score on a standard scale increased by at least 1 point (Dick 1964). Withdrawals and adverse effects were also tabulated
Notes	Prarmacia UK Ltd. supplied the active and placebo drugs used in this study 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	Method of randomization was not described Randomization was restricted in blocks of four to ensure approximately equal numbers of patients allocated to each form of treatment
Allocation concealment (selection bias)	Unclear risk	Not described
Blinding (performance bias and detection bias) All outcomes	Low risk	Double‐blind, double‐dummy
Incomplete outcome data (attrition bias) All outcomes	Low risk	Dropouts appear to be balanced across intervention groups with similar reasons for withdrawal
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