Senior 1991.

Methods	Randomised clinical trial.
Participants	Country: USA. Number randomised: 20. Post‐randomisation dropouts: 1 (5%). Revised sample size: 19. Mean age: not stated. Females: not stated. Symptomatic participants: not stated. AMA positive: not stated. Responders: not stated. Mean follow‐up period (for all groups): all participants followed up for 18 months. Inclusion criteria Symptom status: not stated. AMA status: not stated. Response status: not stated.
Interventions	Participants were randomly assigned to 2 groups. Group 1: UDCA (low) (n = 9). Further details: UDCA (low): 8 mg/kg/day to 12 mg/kg/day for 6 months. Group 2: placebo (n = 10).
Outcomes	None of the outcomes of interest reported.
Notes	Reasons for post‐randomisation dropouts: had coexisting gallstones.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: information not available.
Allocation concealment (selection bias)	Unclear risk	Comment: information not available.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Comment: although a placebo used in this double‐blind trial, unclear whether the placebo was identical.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Comment: although a placebo used in this double‐blind trial, unclear whether the placebo was identical.
Incomplete outcome data (attrition bias) All outcomes	High risk	Comment: there were post‐randomisation dropouts.
Selective reporting (reporting bias)	High risk	Comment: neither mortality nor adverse events reported.
For‐profit bias	High risk	Quote: "and ursodiol supplies provided by Ciba‐Geigy Corporation".
Other bias	Low risk	Comment: no other source of bias.