Mitchell 2001.

Methods	Randomised clinical trial.
Participants	Country: UK/Germany. Number randomised: 26. Post‐randomisation drop‐outs: 0 (0%). Revised sample size: 26. Mean age: 52 years. Females: 7 (26.9%). Separate data for the subgroup with ulcerative colitis: no. Inclusion criteria: Diagnosis of primary sclerosing cholangitis based on standard clinical, biochemical, histological, and radiological features. Absence of evidence of secondary cholangitis, hepatobiliary malignancy, or viral, metabolic, or autoimmune liver disease. Exclusion criteria: Age between 18 and 80 years. Treatment with UCDA in the preceding year. Previous bile duct surgery. Dominant extrahepatic or hilar duct stricture. Previous choledocholithiasis. Recurrent ascending cholangitis. Previous history of variceal haemorrhage. Decompensated liver disease. Cholangiocarcinoma. Active inflammatory bowel disease. Any features of a coexisting liver disease or overlap syndrome. Follow‐up: 24 months.
Interventions	Participants were randomly assigned to 1 of 2 groups. Group 1: moderate‐dose (20 mg/kg/d) UDCA over the period of follow‐up of the study (n = 13). Group 2: identical‐appearing placebo over the period of follow‐up of the study (n = 13).
Outcomes	No outcomes of interest were reported.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: This information was not available.
Allocation concealment (selection bias)	Unclear risk	Comment: This information was not available.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "This preliminary study was designed as a double blind, randomized trial comparing the efficacy and safety of UDCA with that of placebo treatment….The placebo was an identical‐appearing capsule administered in the same quantity and manner".
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "This preliminary study was designed as a double blind, randomized trial comparing the efficacy and safety of UDCA with that of placebo treatment. . .The placebo was an identical‐appearing capsule administered in the same quantity and manner".
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote:"Patients who were lost to follow‐up or died during the study period were included in the final analysis, provided that at least one set of follow‐up data was available". Comment: No post‐randomisation drop‐outs were reported.
Selective reporting (reporting bias)	High risk	Comment: No published protocol was available; nooutcomes of interest were reported.
For‐profit bias	Unclear risk	Comment: This information was not available.
Other bias	Low risk	Comment: no other bias.