Bonderup 2003.

Methods	Randomized, double‐blind, placebo‐controlled. Duration of study was 8 weeks. Stool frequency and stool weight was recorded pre‐ and immediately after stopping treatment. All patients underwent sigmoidoscopy with standardized biopsy protocol pre‐ and post‐treatment. Randomization was performed by the drug company. Medication and placebo were delivered prepackaged with consecutive randomized numbers
Participants	Patients (n = 20, 16 females) aged > 18 years with clinically and histologically confirmed active collagenous colitis Clinical: > 4 stools/day and/or stool weight > 200 g/day averaged over 3 days pre‐treatment. Negative stool samples for pathogens, parasites, and ova. Histological: collagen layer > 10 um Inflammation was graded on a scale (0 to 3) independently by 2 pathologists Patients with other chronic gastrointestinal diseases were excluded, as were those with clinically significant renal or hepatic disease, those who had been treated with anti‐inflammatory drugs (aminosalicylates, corticosteroids, azathioprine) in the previous 3 months or were pregnant or breast feeding
Interventions	Budesonide (9 mg/day for 4 weeks, 6 mg for 2 weeks and 3 mg for 2 weeks) versus placebo for 8 weeks
Outcomes	Primary outcome was the proportion of patients that achieved a clinical or histological response Clinical: reduction of stool frequency and/or stool weight by > 50% Histological: decrease in inflammation grade or reduction in thickness of the collagen layer
Notes	No antiinflammatory drug treatment was allowed during the study period or for 3 months prior to inclusion. During the study antidiarrheal medications were allowed except during the periods of stool sampling. During these periods no other treatments with effects on the GI tract were allowed. NSAIDS were not permitted, but other chronic medications (e.g. ‐ antihypertensives) were allowed
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described in published study
Allocation concealment (selection bias)	Low risk	Randomization was performed centrally by the drug company Medication and placebo were delivered prepackaged with consecutive randomized numbers
Blinding (performance bias and detection bias) All outcomes	Low risk	Quote: "double‐blind" Quote: "The placebo medication was identical in appearance" Quote: "Histopathological evaluation was performed blindly by the two pathologists"
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No description of dropouts or withdrawals
Selective reporting (reporting bias)	Low risk	The primary outcome of clinical remission was reported Histopathological changes were also described
Other bias	Low risk	Study appeared to be free of other forms of bias