Hwang 1993.

Methods	Double‐blind, placebo controlled randomised clinical trial with cross‐over group design (two interventions groups). Trial duration: 3 months. Follow‐up: no patients withdrew.
Participants	Country: China. Number of patients randomised: 12, mean age 58 years (100% females). Inclusion criteria: ‐ elevated serum alkaline phosphatase and gamma‐glutamyl transferase with lack of large bile duct abnormalities; ‐ positive AMA with elevated immunoglobulin M, G or A; ‐ liver biopsy compatible with PBC. Exclusion criteria: ‐ previous PBC treatment.
Interventions	Patients were randomly assigned to receive: Intervention group 1: ursodeoxycholic acid 600 mg/day. Intervention group 2: placebo.
Outcomes	Mortality. Symptoms. Liver biochemistry.
Notes	All patients switched to ursodeoxycholic acid on completion of the six months cross‐over trial.
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 form containing starch'.
Incomplete outcome data (attrition bias) All outcomes	Low risk	It was specified that there were no dropouts or withdrawals, and that all 12 patients completed a six month course of treatment.
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.