Parker 2013.

Study characteristics
Methods	Design: RCT, parallel 2‐arm, single‐site trial Setting: general hospital, Peterborough, UK Recruitment: not stated in paper; ISRCT states trial ran from 2002 to 2012 Maximum follow‐up: 12 months
Participants	200 participants 60 years of age or older with hip fracture whose postoperative Hb on postoperative day 1 or 2 was 8.0 g/dL to 9.5 g/dL 'Transfusion' group: n = 100; mean age (range) = 84.4 (60 to 104) years 'No transfusion' group (aka symptomatic): n = 100; mean age (range) = 84.2 (60 to 97) years
Interventions	Participants had postoperative Hb in a prescribed range (8.0 g/dL to 9.5 g/dL)   For the purposes of this review, the trial author's definitions of 'transfusion' group = liberal, and 'no transfusion' or 'symptomatic' = restrictive   Liberal group: transfusion administered immediately and continued until Hb was maintained at > 10.0 g/dL Restrictive group: no transfusion administered unless prespecified symptoms appeared, specifically, recurrent vasovagal episodes on mobilisation, chest pain of cardiac origin, congestive cardiac failure, unexplained tachycardia, hypotension or dyspnoea thought to be due to anaemia, decreased urine output unresponsive to fluid replacement, or other symptoms felt appropriate by the medical staff
Outcomes	Mobility, mental agility, physical status using American Society of Anesthesiologists grades
Notes	Trial registration (not prospective): ISRCTN61328173 Trial funding: "there was no external funding for this study" (Parker 2013 p 1918) COI statement by investigators: "the author does not have any conflict of interest with this article" (Parker 2013 p 1918)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Randomisation was undertaken using numbered, sealed, opaque envelopes that were prepared before the start of the study"
Allocation concealment (selection bias)	Low risk	Trial used opaque numbered envelopes
Blinding of participants and personnel (performance bias) Objective outcomes	Low risk	Blinding of personnel for this intervention is not feasible, but in our view, for objective outcomes such as mortality (the primary outcome used within this review), we graded risk of bias as 'low' Blinding of participants and personnel was not addressed
Blinding of outcome assessment (detection bias) Objective measures	Low risk	Blinding of mortality (the primary outcome used within this review) is not relevant, and we graded risk of bias as 'low' Blinding of outcome assessment was not addressed
Blinding of outcome assessment (detection bias) Subjective measures	High risk	Blinding of outcome assessor was not addressed for mobility
Incomplete outcome data (attrition bias) All outcomes	High risk	Mobility score was missing for 94 of 200 participants
Selective reporting (reporting bias)	Unclear risk	No reporting bias was apparent; however, trial was retrospectively registered (ISRCTN61328173), and in the absence of a protocol, assessment must remain 'unclear'
Other bias	Low risk	No other biases were apparent