Bonderup 2009.

Methods	Randomized, double‐blind, placebo‐controlled. Randomization was done with a computerized randomization program in blocks of 4 patients Induction: 6 weeks Maintenance: 24 weeks Treatment‐free follow‐up: 24 weeks
Participants	Patients (n = 42) aged > 18 years with clinically (> 3 stools/day over 3 days registration) and histologically (subepithelial collagen layer with a thickness > 10 um, inflammation of the lamina propria, and a lymphocytic infiltrate of the epithelium) confirmed active collagenous colitis plus negative faecal cultures for intestinal pathogens Induction: n = 42 Maintenance: n = 34, 17 in each arm Follow‐up: n = 15, 13 in the budesonide arm and 2 in the placebo arm Patients were excluded if they had been treated with salazopyrine, 5‐aminosalicylic acid, budesonide or a systemic glucocorticoid within 3 months of trial enrolment or treated with ketoconazole during the 7 days before random selection. Other exclusionary criteria were other chronic gastrointestinal diseases (including celiac disease), clinically relevant impairment of kidney or liver function, previous intestinal resection or stoma
Interventions	Induction: 6 weeks, open‐label 9 mg/day budesonide, randomized to maintenance or placebo therapy Maintenance: 24 weeks, budesonide 6 mg/day versus placebo Treatment‐free follow‐up: 24 weeks Patients who relapsed during the maintenance or follow‐up were offered treatment with open‐label budesonide (9 mg/day for 6 weeks, followed by budesonide 6 mg/day for 24 weeks)
Outcomes	Induction: proportion entering clinical/histological remission, randomized to maintenance or placebo therapy after 6 weeks Maintenance: proportion maintaining clinical/histological remission after 24 weeks Treatment‐free follow‐up: proportion maintaining clinical/histological remission 24 weeks Clinical remission was defined as mean stool frequency of < 3 per day *Each patient underwent colonoscopy or sigmoidoscopy pre‐treatment. All were scheduled to undergo sigmoidoscopy at relapse or at the end of treatment, but this was only performed in 21 patients Other outcome measures included: fecal weight (g/day), safety data, maintained histological response (collagen layer <10 um and inflammation score <1), the time to relapse and the rate of relapse after stopping treatment
Notes	Data from the 24 weeks of the study only were included as the primary outcome measure, as this was the duration of active treatment with budesonide or placebo
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Computer‐generated block randomisation"
Allocation concealment (selection bias)	Low risk	Allocation sequence appears to be centrally generated
Blinding (performance bias and detection bias) All outcomes	Low risk	Quote: "double‐blind" Quote: "budesonide 6 mg once a day (2 x 3 mg capsules) or matching placebo" Quote: "blinded follow‐up period (the randomisation code was unbroken until completion of follow‐up, such that neither patients nor physicians knew which treatment the patient had received during maintenance therapy)"
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "All analyses were completed on an intention‐to‐treat basis; premature discontinuation of treatment was considered as relapse in both treatment arms" Quote: "Two patients, one in each group, discontinued maintenance treatment because of adverse events"
Selective reporting (reporting bias)	Low risk	All outcomes were reported
Other bias	Low risk	Study appeared to be free of other forms of bias