Gregersen 2015.

Methods	Randomised controlled trial Single‐centre study (Departments of Geriatrics and Orthopaedics, Aarhus University Hospital, Aarhus), Denmark Dates enrolled: 18 January 2010 to 6 June 2013 Follow‐up period: 90 days (record of mortality and physical ability)
Participants	284 participants of which 25% were men Inclusion criteria: clinical diagnosis of hip fracture surgery treatment postoperative anaemia: 6‐7 mmol/L up to the 6th day post operation aged ≥ 65 years admitted from nursing home or sheltered housing facilities for unilateral hip fracture surgery written assent Exclusion criteria: active cancer pathological fractures inability to understand or speak Danish without an interpreter red blood cell transfusion refusal fluid overload irregular erthrocyte antibodies previous participation in a trial Mean (SD) age in the liberal transfusion threshold: 88 (6.9) years Mean (SD) age in the restrictive transfusion threshold: 86 (6.8) years Number of men per intervention: 34/36
Interventions	Liberal transfusion strategy: transfusions given when the haemoglobin concentration was < 7 mmol/L (11.3 g/dL) Restrictive transfusion strategy: transfusions given when the haemoglobin concentration was < 6 mmol/L (9.7 g/dL) Haemoglobin concentration was measured daily during the first 3 postoperative days then at least once during the following 4‐6 days and at least once weekly for the subsequent 3 weeks Number of participants randomised per intervention: 140/144 Number of participants included in the analysis of the primary outcome: 140/144
Outcomes	Primary outcome: functional ability 10 days post operation. Measured by the CAS, New Mobility Score (NMS) and Modified Barthel Index (MBI) Secondary outcomes: mortality at 90 days post operation (main causes of death listed) quality of life at 90 days post operation, measured by the Depression List (DL) biochemical markers: C‐reactive protein and leukocyte count during the first 30 days post operation time to first treatment‐requiring infection indicated by a positive urine culture or suspected infection
Notes	Original details of the trial were taken from the protocol uploaded to clinicaltrials.gov; the first reports of the trial following trial completion were presented in conference format Email communication with the author on 11 December 2014 resulted in us receiving a copy of the final (unpublished) version of the manuscript for this trial with outcome data and information that allowed us to complete a risk of bias assessment. We added the data and information to the text and tables for this review. Subsequently the manuscript for this trial was published in Acta Orthopaedica; currently online (March 2015) 88% of participants in the restrictive transfusion threshold group and 87% of participants in the liberal transfusion threshold group received iron supplementation while on the trial The trial stratified participants at the time of randomisation between people who were living in sheltered housing and people living in a nursing home. Subgroup analyses were conducted on place of residence within the trial. Except for some observations on length of hospital stay, we reported the analysis by intervention alone within this review
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Randomization was provided by an allocation concealment process in the web based clinical trial support system." Participants were allocated to the trial's intervention groups by the project manager entering the participant's civil registration number into the computer program (page 5 of unpublished trial manuscript)
Allocation concealment (selection bias)	Low risk	"Randomization was provided by an allocation concealment process in the web based clinical trial support system" (page 5 of unpublished trial manuscript)
Blinding of participants (performance and detection bias)	Low risk	The central computer programme allocated each participant to one of the trial's two intervention groups. The project manager entered the patient's civil registration number into the computer programme and passed on the randomisation result to the electronic patient record which was available to the hospital staff in the Orthopaedic and Geriatric wards: the wards in which the transfusions were to be administered The trial stated that the participants, their relatives and the outcome assessors were blinded to the result of the randomisation and to information on the participant's haemoglobin concentration levels (page 5 of unpublished trial manuscript)
Blinding of personnel (performance bias)	High risk	The trial stated that the participants, their relatives and the outcome assessors were blinded to the result of the randomisation and to information on the participant's haemoglobin concentration levels. No information was reported as to whether study personnel were blinded to treatment allocation However, there were 8 (3%) deviations from protocol in each intervention group In the liberal transfusion threshold group, there were 4 protocol deviations due to inattention to haemoglobin concentrations and in 4 cases physicians prescribed more blood In the restrictive transfusion threshold group, there were 6 protocol deviations due to inattention to haemoglobin concentrations and in 2 cases physicians refused to prescribe red blood cell transfusion
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Physical and cognitive outcomes were assessed by 2 occupational therapists blinded to treatment allocation Dates (and causes) of deaths up to 90 days post surgery were obtained from the Danish Civil Registration System (and from death certificates from the Danish Health and Medicine Authority) (page 7 of unpublished trial manuscript)
Incomplete outcome data (attrition bias) All outcomes	Low risk	Intention‐to‐treat and per‐protocol analyses conducted. Similar numbers (12 in each group) were dropped from the per‐protocol analysis. All participants included in the primary analyses
Selective reporting (reporting bias)	Low risk	All outcomes outlined as being of interest to the trial in the trial protocol on clinicaltrials.gov were reported on in the unpublished trial manuscript
Other bias	Unclear risk	Insufficient data to assess low or high risk of bias No evidence of baseline imbalance between the 2 trial groups and no details were reported as to any protocol violations