Baert 2002.

Methods	Randomized, double‐blind, placebo‐controlled. Duration of treatment was 8 weeks, plus an 8 week treatment‐free follow‐up, for a total of 16 weeks
Participants	Patients (n = 28) aged > 18 years with clinically and histologically confirmed active collagenous colitis Clinical: minimum 3 semi‐loose or loose stools per day for at least 8 weeks, no other significant cause on history/physical, negative stool examination for pathogens, parasites, and C. difficile toxin and no macroscopic inflammation on colonoscopy (and no other endoscopic findings other than diverticulosis or diminutive polyps). Histological: subepithelial collagen band > 10 um thick and typical feathery appearance of the inferior border; increased mixed inflammatory cell infiltrate in lamina propria. Cases with overlapping features with lymphocytic colitis were allowed if the collagen band was a predominant finding Patients with significant gastrointestinal disease (except controlled gastroesophageal reflux disease and celiac disease on a long‐term gluten‐free diet) were excluded
Interventions	Budesonide (Budenofalk) 9 mg/day (n = 14) versus placebo (n = 14) for 8 weeks
Outcomes	Proportion of patients achieving clinical and/or histological response Clinical: reduction of stool frequency in last week of treatment by at least 50%. Histological: statistically significant reduction of the infiltrate in the lamina propria and/or a significant reduction in the mean thickness of the collagen band Other end‐points were impact on abdominal pain, stool consistency score, patient's general well‐being, amount of time necessary to induce remission, safety of budesonide, and long‐term clinical effects of budesonide including the relapse rates after weaning or discontinuing budesonide All patients kept a diary throughout the study period. Each patient underwent colonoscopy and standardized biopsy protocol pre‐ and post‐treatment
Notes	Data from first 8 weeks of the study only were included in the analysis, as this was the duration of treatment with active drug or placebo. Five patients that failed to meet the inclusion criteria after being randomized into the trial (upon review of their stool diaries) were excluded from the analysis. Medications that could possibly affect stool frequency or the natural history of the disease were not allowed during the study and were discontinued (with an appropriate wash‐out period) before inclusion. Other chronic medications were allowed to be continued as long as the intake remained stable throughout the study period. 3 patients (2 placebo) dropped out of the study
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	The method of randomization was not described
Allocation concealment (selection bias)	Low risk	Randomization was done centrally by the company delivering the drugs and placebo
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Quote: "double‐blind" Quote: "All biopsies were randomly read by 2 blinded expert pathologists"
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "All calculations were made on an intention‐to‐treat basis" Quote: "Three patients dropped out of the study (2 placebo), one for noncompliance and 2 because of treatment failure" Intention‐to‐treat was followed for clinical response Intention‐to‐treat was not followed for histologic response (denominators of 13 and 12 for the treatment and placebo group respectively)
Selective reporting (reporting bias)	Low risk	All primary outcomes were reported. Time to clinical remission was not directly reported in text, but it was interpretable from one of their published figures (Figure 1)
Other bias	Low risk	Study appeared to be free of other forms of bias