title: Effect of restrictive versus liberal red cell transfusion strategies on haemostasis: systematic review and meta-analysis.
abstract: Red cells play a key role in normal haemostasis in vitro but their importance clinically is less clear. The objective of this meta-analysis was to assess if correction of anaemia by transfusing red cells at a high haemoglobin threshold (liberal transfusion) is superior to transfusion at a lower haemoglobin threshold (restrictive transfusion) for reducing the risk of bleeding or thrombotic events. We searched for randomised controlled trials in any clinical setting that compared two red cell transfusion thresholds and investigated the risk of bleeding. We searched for studies published up to October 19, 2016 in The Cochrane Central Register of Controlled Trials, MEDLINE, PubMed, Embase, and the Transfusion Evidence Library and ISI Web of Science. Relative risks (RR) or Peto Odds Ratios (pOR) were pooled using a random-effect model. Nineteen randomised trials with 9852 participants were eligible for inclusion in this review. Overall there was no difference in the risk of any bleeding between transfusion strategies (RR 0.91, 95 % confidence interval [CI] 0.74 to 1.12). The risk of severe or life-threatening bleeding was lower with a restrictive strategy (RR 0.75, 95 % CI 0.57 to 0.99). There was no difference in the risk of thrombotic events (RR 0.83, 95 % CI 0.61 to 1.13). The risk of any bleeding was not reduced with liberal transfusion and there was no overall difference in the risk of thrombotic events. Data from the included trials do not support aiming for a high haemoglobin threshold to improve haemostasis. PROSPERO registration number CRD42016035519.
authors.affiliation: Dr. Michael J. R. Desborough, MRCP FRCPath, NHS Blood and Transplant, John Radcliffe Hospital, Headley Way, Oxford, OX3 9DU, UK, Tel.: +44 1865 447900, Fax: +44 1865 387957, E-mail: Michael.desborough@ouh.nhs.uk.
authors.forename: Michael J R
authors.initials: MJR
authors.lastname: Desborough
authors.forename: Katherine S
authors.initials: KS
authors.lastname: Colman
authors.forename: Babette W
authors.initials: BW
authors.lastname: Prick
authors.forename: Johannes J
authors.initials: JJ
authors.lastname: Duvekot
authors.forename: Connor
authors.initials: C
authors.lastname: Sweeney
authors.forename: Ayodele
authors.initials: A
authors.lastname: Odutayo
authors.forename: Vipul
authors.initials: V
authors.lastname: Jairath
authors.forename: Carolyn
authors.initials: C
authors.lastname: Doree
authors.forename: Marialena
authors.initials: M
authors.lastname: Trivella
authors.forename: Sally
authors.initials: S
authors.lastname: Hopewell
authors.forename: Lise J
authors.initials: LJ
authors.lastname: Estcourt
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Stanworth
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000740:Anemia / Q000097:blood / Q000175:diagnosis / Q000628:therapy*; D015415:Biomarkers / Q000097:blood; D016009:Chi-Square Distribution; D002675:Child, Preschool; D017707:Erythrocyte Transfusion / Q000009:adverse effects / Q000379:methods*; D005260:Female; D006454:Hemoglobins / Q000378:metabolism; D006470:Hemorrhage / Q000209:etiology; D006487:Hemostasis; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D018570:Risk Assessment; D012307:Risk Factors; D013927:Thrombosis / Q000209:etiology; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D006454:Hemoglobins
keywords: Haemorrhage; myocardial infarction; stroke; transfusion; venous thromboembolism