De la Mora 1994.

Methods	Randomised trial. Follow‐up: information not provided.
Participants	Patients with PBC (n = 28) from one centre in Mexico.
Interventions	Experimental: ursodeoxycholic acid (details were not given). Control: placebo.
Outcomes	Serum cholesterol.
Notes
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	Unclear risk	'Placebo' employed, but it is not known if it was indeed double blind.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	The report gave the impression that there had been no dropouts or withdrawals, but this was not specifically stated.
Selective reporting (reporting bias)	Unclear risk	Not all pre‐defined, or clinically relevant and reasonably expected outcomes are reported on or are not reported fully, or it is unclear whether data on these outcomes were recorded or not.
Other bias	Unclear risk	The trial may or may not be free of information that could put it at risk of bias.