Nielsen 2014.

Methods	Randomised clinical trial
Participants	Participants were at least 18 years of age and scheduled for elective hip revision surgery. Liberal: n = 33; median age (5% to 95% range) = 72 (54 to 89) years Restrictive: n = 33; median age (5% to 95% range) = 68 (43 to 86) years
Interventions	The participants were randomized to a restrictive strategy receiving transfusion of RBC at a Hb of 7.3 g/dL (4.5 mmol/L) or a liberal strategy receiving transfusion of RBC at a Hb of 8.9 g/dL (5.5 mmol/L). The target level of haemoglobin in the restrictive group was 7.3 g/dL to 8.9 g/dL and above 8.9 g/dL in the liberal group.
Outcomes	The primary outcome was the 'Timed up and go' test. Other outcomes were pneumonia, wound infection, gastrointestinal complications, dizziness, hypotension, fatigue, deep vein thrombosis, and fall.
Notes	‐
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	A dedicated computer program (Idefix) was used after entering participants' baseline data. The allocation was written on a form, which was kept in the investigator's office, and the allocation could only be accessed by the investigator in charge of administrating red blood cells.
Allocation concealment (selection bias)	Low risk	Only 1 investigator had access to the programme. Investigators at the other hospital had to call this investigator to randomise.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	The allocation and Hb during the testing period were concealed from the participants but the investigator, the staff in the operating room, and the staff at the ward could not be blinded.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	The physiotherapist testing the participant was blinded, but it was not stated who reviewed medical records for other outcomes.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No attrition bias was apparent.
Selective reporting (reporting bias)	Low risk	No reporting bias was apparent.
Other bias	Low risk	No other bias was apparent.