Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomly allocated: no details
Allocation concealment (selection bias)	Unclear risk	Unclear
Blinding of participants and personnel (performance bias)	High risk	Unlikely
Blinding of outcome assessment (detection bias)	Low risk	Outcome assessors (for POCD) were blinded to the anaesthetic technique
Incomplete outcome data (attrition bias)	Low risk	Four participants lost to follow‐up
Selective reporting (reporting bias)	High risk	Mortality given up to one year (although exact group not given). Presence/absence of complications related to the anaesthetic techniques not reported
Other bias	Unclear risk	Higher proportion of Ischaemic heart disease (18 vs 11) and of cerebrovascular disease (four vs two) in the epidural group