| Methods |
Multi‐centre, randomised, double‐blind, double‐dummy, parallel group study |
| Participants |
Adult patients (18 to 75 years) with a mild to moderate (less than endoscopic score of 4) attack of ulcerative colitis (N = 168) |
| Interventions |
Olsalazine 3 g/day (n = 88) or mesalazine (Claversal) 3 g/day (n = 80) for 12 weeks |
| Outcomes |
The primary outcome was endoscopic remission (defined as a score of 0 or 1 on the Rachmilewitz index). Secondary outcomes included clinical remission (< 1 on modified Rachmilewitz index), physician's global assessment on four‐point scale |
| Notes |
|
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Unclear risk |
Not described |
| Allocation concealment (selection bias) |
Low risk |
Centralized randomization |
| Blinding (performance bias and detection bias)
All outcomes |
Low risk |
Double‐blind, double‐dummy |
| Incomplete outcome data (attrition bias)
All outcomes |
Low risk |
Twenty‐five per cent drop out rate. However, drop‐outs 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 |
