Heathcote 1994.

Methods	Randomised clinical trial.
Participants	Country: Canada. Number randomised: 222. Post‐randomisation dropouts: not stated. Revised sample size: 222. Mean age: 56 years. Females: 206 (92.8%). Symptomatic participants: not stated. AMA positive: not stated. Responders: not stated. Mean follow‐up period (for all groups): all participants followed up for 24 months. Inclusion criteria Symptom status: symptomatic and asymptomatic participants. AMA status: not stated. Response status: not stated. Exclusion criteria Aged < 18 years. On transplant list. Needed to take enzyme‐inducing drugs. Pregnant. Other medical illnesses with anticipated life expectancy < 5 years.
Interventions	Participants were randomly assigned to 2 groups. Group 1: UDCA (moderate) (n = 111). Further details: UDCA: 14 mg/kg/day for 2 years. Group 2: placebo (n = 111).
Outcomes	Mortality, liver transplantation.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: information not available.
Allocation concealment (selection bias)	Low risk	Quote: "Randomization was done separately at each centre by the study pharmacist using consecutive identification numbers, and patients were stratified according to whether they were symptomatic or asymptomatic".
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "Once informed consent was obtained from the patients, double‐blind randomization to UDCA or an identical placebo (1 : 1) was conducted".
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "Once informed consent was obtained from the patients, double‐blind randomization to UDCA or an identical placebo (1 : 1) was conducted".
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Comment: unclear whether the authors have reported the outcomes on all randomised participants.
Selective reporting (reporting bias)	High risk	Comment: adverse events not reported.
For‐profit bias	High risk	Quote: "Study medications kindly provided by Interfalk Canada and Jouveinal Inc., Quebec, Canada".
Other bias	Low risk	Comment: no other source of bias.