Wildt 2006.

Methods	Randomized, double‐blind, placebo‐controlled trial at 4 Danish centres. Randomization was in a 2:1 fashion (probiotic:placebo)
Participants	Patients (n = 36*, therefore n = 29, 2 men) aged ≥18 years with confirmed histological diagnosis of collagenous colitis that is active and untreated for at least 4 weeks prior to study inclusion. Clinically active disease is defined as > 21 liquid or soft stools per week or stool weight of > 200 g/day for at least 4 weeks Histological diagnosis required "a subepithelial collagen band > 10 um in a well oriented section of the mucosa and inflammation of the lamina propria with infiltration of predominantly lymphocytes and plasma cells" Exclusion criteria included: pregnancy or breast feeding, chronic liver or kidney disease, severe vascular or cardiopulmonary disease, malignancy, immunosuppressive disease or treatment, known inflammatory bowel disease besides collagenous colitis (including celiac disease), evidence of infectious diarrhea, prior gastrointestinal surgery other than appendectomy, and malabsorption syndromes. Treatment with aminosalicylates, antibiotics, cholestyramine, nonsteroidal anti‐inflammatory drugs, and steroids was not allowed 4 weeks prior to study entrance
Interventions	Probiotic (AB‐Cap‐10; two capsules twice daily) or placebo (2 capsules twice daily) for 12 weeks. Loperamide and opioids were allowed during the study
Outcomes	Primary outcome was the proportion of patients with a at least a 50% reduction in the number of stools per week at 12 weeks Secondary outcomes: changes in bowel frequency, stool consistency, stool weight, abdominal pain and bloating, histopathology scores from biopsies, Short Inflammatory Bowel Disease Questionnaire (SIBDQ) scores, use of antidiarrhoeal medication, and adverse events Histological scores from: significant change in three parameters: reduction of thickness of the collagen band; improvement in the degree of inflammation of the lamina propria; improvement of degeneration of surface epithelium The study period was 17 weeks (12 weeks treatment + 5 weeks follow up) with patients being assessed at weeks ‐1, 0, 4, 6, 12, and 16. All patients kept a diary throughout the study period
Notes	AB‐Cap‐10 is a mixture of L. acidophilus strain LA‐5 and B. animalis subsp. lactis strain BB‐12. Each capsule contained 0.5 x 10^10 colony‐forming units of each bacterium, leading to a total delivery of 1 x 10^10 CFU per capsule SIBDQ; a 10‐item questionnaire measuring health‐related quality of life [HRQOL] intended for patients with Crohn’s disease and ulcerative colitis *Seven patients that failed to meet the inclusion criteria after being randomized into the trial (six patients had lymphocytic colitis and one had a subepithelial collagen band < 10 um thick) are excluded from the analysis Study enrolment was stopped early due to difficulties recruiting patients
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomization was completed in blocks of 9 using a table of random numbers
Allocation concealment (selection bias)	Unclear risk	Method of randomization not described in study
Blinding (performance bias and detection bias) All outcomes	Low risk	Quote: "double‐blind" Quote: "Placebo medication (Chr. Hansen A/S) was identical in appearance, size, and taste"
Incomplete outcome data (attrition bias) All outcomes	Low risk	3 probiotic treatment patients dropped out because of lack of response Quote: "When data at week 12 were missing because of withdrawals, the last observation was carried forward"
Selective reporting (reporting bias)	Low risk	All outcome reported. One post hoc analysis noted
Other bias	Low risk	Study appeared to be free of other forms of bias