Leuschner 1989.

Methods	Double‐blind, placebo controlled randomised clinical trial with parallel group design (two interventions groups). Trial duration: 9 months. Follow‐up: 2 patients from placebo arm left the trial.
Participants	Country: Germany. Number of patients randomised: 20, mean age not provided (90% females). Inclusion criteria: PBC defined as at least three of the following: ‐ alkaline phosphatase > 1.7 times upper normal limit; ‐ gamma‐glutamyl transferase > 5.0 times upper normal limit; ‐ immunoglobulin M > 2.0 times upper normal limit; ‐ positive AMA plus no obstruction of the extrahepatic biliary tract. Exclusion criteria: ‐ oesophageal varices; ‐ ascites; ‐ pancreatitis; ‐ cardiac failure or renal failure; ‐ pregnancy; ‐ age < 30 years; ‐ any previous PBC treatment within the four weeks; ‐ alcohol or drug abuse.
Interventions	Patients were randomly assigned to receive: Intervention group 1: ursodeoxycholic acid 10 mg/kg/day, divided into two doses, n = 10. Intervention group 2: placebo, n = 10.
Outcomes	Outcome measure(s): ‐ mortality; ‐ symptoms; ‐ liver biochemistry; ‐ liver histology.
Notes	Two patients from the placebo arm left the trial for reasons unrelated to the trial and are not considered in the analysis of the results.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	The trial is described as randomised, but the method of sequence generation was not specified.
Allocation concealment (selection bias)	Unclear risk	The trial was described as randomised but the method used to conceal the allocation was not described, so that intervention allocations may have been foreseen in advance of, or during, enrolment.
Blinding (performance bias and detection bias) All outcomes	Low risk	It was reported that placebo was 'identical tablet'.
Incomplete outcome data (attrition bias) All outcomes	Low risk	The numbers and reasons for dropouts and withdrawals in all intervention groups were described.
Selective reporting (reporting bias)	Low risk	All expected outcomes are reported.
Other bias	Low risk	The trial appears to be free of information that could put it at risk of bias.