Carson 2013.

Methods	Randomised clinical trial
Participants	Participants with acute myocardial infarction or undergoing cardiac catheterisation with Hg less than 10 g/dL Liberal group: n = 55; mean (SD) age = 67.3 (13.6) years Restrictive group: n = 55; mean (SD) age = 74.3 (11.1) years
Interventions	The liberal group received 1 unit of red blood cells following randomisation and enough blood to maintain haemoglobin above 10 g/dL. The restrictive group received transfusion if participants developed symptoms of anaemia or if Hg fell below 8 g/dL.
Outcomes	Primary outcomes were death, myocardial infarction, and unscheduled revascularisation. Secondary outcomes were 30‐day and 6‐month mortality, long‐term mortality, myocardial infarction, congestive heart failure, stroke, thromboembolism, and pneumonia.
Notes	‐
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	A computer programme generated allocation sequence.
Allocation concealment (selection bias)	Low risk	The trial used central telephone randomisation.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Participants and physicians were not blinded, but this was unlikely to impact the trial.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	All primary and most secondary outcomes were assessed blindly.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Only 1 of 110 participants was lost to follow‐up.
Selective reporting (reporting bias)	Low risk	All outcomes were reported.
Other bias	Low risk	No other biases identified.