Umbrales de transfusión para guiar la transfusión de eritrocitos
Information
- DOI:
- https://doi.org/10.1002/14651858.CD002042.pub5Copy DOI
- Database:
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- Cochrane Database of Systematic Reviews
- Version published:
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- 21 December 2021see what's new
- Type:
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- Intervention
- Stage:
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- Review
- Cochrane Editorial Group:
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Cochrane Injuries Group
- Copyright:
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- Copyright © 2021 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
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Authors
Contributions of authors
For the 2021 update
Carson, Stanworth and Dennis contributed equally to this review update. Carson and Stanworth continue to provide overall leadership of the review updates with clinical input; they screened abstracts and titles identified in the searches, and applied inclusion and exclusion criteria. Carson, Stanworth and Dennis extracted data, and assessed risk of bias of trials. Carson entered the data into Review Manager 5.4 and, with Trivella and Dennis, performed the initial analyses. Dennis and Trivella provided methodological and statistical input and assurance (Review Manager 5a). Stanworth and Carson prepared the first draft of the manuscript. Nareg Roubinian reviewed the accuracy of data and assisted with preparation of the manuscript. Fergusson provided methodological and statistical expertise and assisted with final drafts of the of the manuscript. Triulzi and Hébert reviewed the manuscript and provided content expertise. Doree performed additional literature searches.
For the 2016 update
Carson and Stanworth screened abstracts and titles identified in the searches, applied inclusion and exclusion criteria, and assessed the quality of trials. Stanworth led the quality review, and Carson entered the data into Review Manager 5.3, performed initial analyses, and prepared the first draft of the manuscript (Review Manager 5a). Roubinian checked the accuracy of data and assisted with preparation of the manuscript. Fergusson provided methodological and statistical expertise and assisted with preparation of the manuscript. Triulzi and Hébert reviewed the manuscript and provided content expertise. Doree performed additional literature searches.
For the 2012 review
Paul Carless performed original database literature searches, screened abstracts and titles for relevant articles, obtained relevant papers, applied inclusion/exclusion criteria to retrieved papers, extracted data from trials, quality‐assessed trials, entered data into Meta‐View 4.1, entered all study details into Review Manager 5.1, and co‐wrote the review (Review Manager 5b). Jeffrey Carson screened abstracts and titles for relevant articles, obtained relevant papers, applied inclusion/exclusion criteria to retrieved papers, extracted data from trials, quality‐assessed trials, entered data and all study details into Review Manager 5.1, and co‐wrote the review. Paul Hébert reviewed the manuscript and provided expertise with analysis and content expert opinion.
Sources of support
Internal sources
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National Institute for Health Research (NIHR), UK
Provides support for the Cochrane Injuries Group, which employs authors MHT and JD
External sources
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No sources of support provided
Declarations of interest
We have considered disclosures relevant to this review.
Jeffrey Carson reports being the chief investigator on three trials included in this review (Carson 1998; Carson 2011 (FOCUS); Carson 2013). He has received multiple grants supporting his institution from the US National Institutes of Health. He has been involved with guideline development for red cell transfusions in the Association for the Advancement of Blood & Biotherapies (AABB). He has received a grant from the US National Institutes of Health to evaluate transfusion thresholds in patients with acute myocardial infarction in an ongoing trial (MINT ‐ NCT02981407).
Carolyn Dorée: nothing to declare.
Dean Fergusson reports being an author on three completed trials included within this review (Hébert 1999; Mazer 2017 (TRICS III); Shehata 2012). He was a Co‐Principal Investigator on the TRICSIII trial (Mazer 2017); he is a member of the Steering Committee for the ongoing MINT trial (NCT02981407).
Paul Hébert reports being an author on three completed trials identified in this review (Hébert 1995; Hébert 1999; Lacroix 2007 (TRIPICU). He is the lead investigator on the study NCT02619136, the Canadian pilot study for MINT (NCT02981407, for which he is a member of the Executive Committee); he has published six non‐Cochrane reviews in this area. He serves on a guideline panel for the American College of Chest Physicians (ACCP) and has written several editorials for leading journals concerning transfusion triggers.
Nareg Roubinian: nothing to declare.
Simon Stanworth reports being the chief investigator on one trial included in this review (Stanworth 2020); a coauthor on another (Gillies 2020 (RESULT‐NOF)); and is a co‐investigator on four ongoing trials (ISRCTN17438123; ACTRN12619001053112; NCT03871244; Morton 2020). He has received funding for four RBC transfusion trials, including three in patients with haematological malignancy. He has published three non‐Cochrane reviews in this area.
Darrell Triulzi is a member of the Steering Committee for the ongoing MINT trial (NCT02981407) and a member of the scientific advisory board for Fresenius‐Kabi.
Jane Dennis was employed by Cochrane Injuries during her involvement in development of the review.
Marialena Trivella was employed by Cochrane Injuries during her involvement in development of the review.
Data extraction for all trials was checked by NR. Final decisions on risk of bias assessments were made by review authors not involved in trials as researchers.
Acknowledgements
In this 2021 update, we acknowledge the contributions of co‐authors to the Carson 2018 review, which focused on patients with cardiovascular disease. We also thank Drs DeZern, Villaneuva, and Webert for providing additional data. We thank peer reviewers Jeannie Callum (Queen’s University, Kingston, Canada) and Paul M Ness MD (Professor of Pathology and Medicine, Johns Hopkins University School of Medicine, USA) for their constructive comments, which we believe improved this manuscript profoundly. We gratefully acknowledge the work of Dr Catriona Gilmour‐Hamilton (Oxford, UK) and that of the patient engagement group she co‐ordinates (Oxford Blood Group) in the development of the Plain Language Summary. We thank statisician Dr Kerry Dwan (Cochrane Editorial & Methods Department) for valuable comments and assistance. The review authors are especially thankful for the work and enthusiasm of Dr Elizabeth Royle at all steps of this 2021 review update, including extensive editorial assistance. We also acknowledge administrative support from Kim Lacey for this 2021 update.
We acknowledge the contributions of a number of individuals to prior editions, all of which have informed subsequent updates. These include Suzanne Hill (World Health Organization), the first author of the original version, Hill 2000, and the 2005 update of the review, and Paul Carless, who was first author on the update published in 2010 (Carless 2010b). We also acknowledge the contributions of Kim Henderson to the original review first published in 2000.
We acknowledge David Henry (Institute for Clinical Evaluative Sciences) and Brian McClelland, who co‐wrote reviews up to 2010; Katharine Ker (London School of Hygiene & Tropical Medicine), who undertook the following tasks for the 2010 update: screened search output, obtained articles, applied inclusion/exclusion criteria to retrieved papers, assessed risk of bias, extracted data, performed data analysis, and revised the text of the review. We thank Karen Blackhall (former Injuries Group Trials Search Co‐ordinator), who ran electronic database searches in 2009 and 2011.
For the 2016 update, we thank Deirdre Beecher (former Injuries Group Information Specialist), who ran the searches in 2015, and Sarah Dawson (former Injuries Group Information Specialist), who updated the searching section in 2016. We are especially appreciative to Marialena Trivella, Emma Sydenham, Elizabeth Royle, and the other editors at Cochrane Injuries for their extensive assistance in the analysis and presentation of this version of the review.
This project is independent research funded by the National Institute for Health Research (Systematic Reviews Infrastructure Funding, NIHR129465‐Cochrane Injuries Group). The views expressed in this publication are those of the author(s) and not necessarily those of the NHS, the National Institute for Health Research, or the Department of Health and Social Care.
Version history
| Published | Title | Stage | Authors | Version |
| 2021 Dec 21 | Transfusion thresholds for guiding red blood cell transfusion | Review | Jeffrey L Carson, Simon J Stanworth, Jane A Dennis, Marialena Trivella, Nareg Roubinian, Dean A Fergusson, Darrell Triulzi, Carolyn Dorée, Paul C Hébert | |
| 2016 Oct 12 | Transfusion thresholds and other strategies for guiding allogeneic red blood cell transfusion | Review | Jeffrey L Carson, Simon J Stanworth, Nareg Roubinian, Dean A Fergusson, Darrell Triulzi, Carolyn Doree, Paul C Hebert | |
| 2012 Apr 18 | Transfusion thresholds and other strategies for guiding allogeneic red blood cell transfusion | Review | Jeffrey L Carson, Paul A Carless, Paul C Hebert | |
| 2010 Oct 06 | Transfusion thresholds and other strategies for guiding allogeneic red blood cell transfusion | Review | Paul A Carless, David A Henry, Jeffrey L Carson, Paul PC Hebert, Brian McClelland, Katharine Ker | |
| 2000 Jan 24 | Transfusion thresholds and other strategies for guiding allogeneic red blood cell transfusion | Review | Suzanne Hill, Paul A Carless, David A Henry, Jeffrey L Carson, Paul PC Hebert, Kim M Henderson, Brian McClelland | |
Differences between protocol and review
The following differences were applied in this 2021 version of the review.
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We changed the title of the review from "Transfusion thresholds and other strategies for guiding allogeneic red blood cell transfusion" to "Transfusion thresholds for guiding red blood cell transfusion".
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The authors of the review have changed ‐ two new authors have been added (Marialena Trivella and Jane Dennis).
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We clarified the outcome of blood transfusion as a measure of treatment implementation and reported and analysed these elements more clearly.
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We added a new secondary outcome (transfusion‐specific reactions).
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We added quality of life (QOL) to data items collected under 'function'.
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Our summary of findings table now reports on infections as a composite category, rather than 'pneumonia' as a specific one.
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We have added details of random‐effects analysis into the data synthesis section.
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We no longer include an estimate of optimal information size (sample size calculations for trials to yield reliable information on mortality assuming baseline mortality at 30 days), given the breadth of clinical contexts included within this review.
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We have divided risk of bias assessment for outcome assessment by objective (mortality) and subjective (function, QOL) measures.
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We have omitted sensitivity analysis on the basis of outcome assessment for mortality, considering that the objective nature of the outcome makes blinding unimportant. Should future versions of the review include data suitable for meta‐analysis for the outcomes of function and fatigue, we will conduct sensitivity analyses on the basis that blinding is relevant in such cases.
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We reviewed our ratings for bias under the domain of 'Selective outcome reporting'.
The following differences were applied in the 2016 version of the review.
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The primary outcome changed from "the proportion of patients 'at risk' who were transfused with red blood cells", to "30‐day mortality". Previously, 30‐day mortality was a secondary outcome. The proportion of participants 'at risk' who were transfused with red blood cells became a secondary outcome. The primary outcome was changed because mortality is a more clinically relevant outcome and the number of participants enrolled in trials provided sufficient power to examine this outcome.
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Sample size calculations that assumed a baseline 30‐day mortality of 9% for restrictive transfusion, 90% power, alpha level of 0.05, indicated that to detect a 15%, 20%, or 25% relative decrease in mortality with the use of liberal transfusion, a trial would need to enrol 17,500, or 9600, or 6000 participants, respectively.
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We added one new exclusion criterion: we excluded trials that were not designed to include any clinical outcomes relevant to this review.
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We added a new sensitivity analysis: registered trials versus unregistered trials.
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We separated blinding of participants and personnel from blinding of outcome assessment.
Keywords
MeSH
Medical Subject Headings (MeSH) Keywords
Medical Subject Headings Check Words
Humans;
PICOs
Flow of studies for 2021 update
'Risk of bias' graph: review authors' judgements about each 'Risk of bias' item presented as percentages across all included trials. Forty‐eight trials are included in this review.
'Risk of bias' summary: review authors' judgements about each methodological quality item for each included trial
Funnel plot of comparison: 1 Mortality, outcome: 1.1 30‐Day mortality
Funnel plot of comparison: 2 Blood transfusions, outcome: 2.1 Participants exposed to blood transfusion (all trials)
Funnel plot of comparison: 2 Subgroup analysis by prospective registration, outcome: 2.1 30‐Day mortality
Comparison 1: Mortality at 30 days, Outcome 1: 30‐Day mortality
Comparison 1: Mortality at 30 days, Outcome 2: 30‐Day mortality subgroup by restrictive haemoglobin level
Comparison 1: Mortality at 30 days, Outcome 3: 30‐Day mortality subgroup analysis by clinical specialties
Comparison 1: Mortality at 30 days, Outcome 4: 30‐Day mortality by clinical specialties: myocardial infarction vs all others
Comparison 1: Mortality at 30 days, Outcome 5: Mortality by cardiac surgery, vascular surgery, myocardial infarction, and all others
Comparison 2: Subgroup analysis by prospective registration, Outcome 1: 30‐Day mortality
Comparison 3: Sensitivity analysis by allocation concealment, Outcome 1: 30‐Day mortality
Comparison 4: Mortality: other time intervals, Outcome 1: Hospital mortality
Comparison 4: Mortality: other time intervals, Outcome 2: 90‐Day mortality
Comparison 4: Mortality: other time intervals, Outcome 3: 6‐Month mortality
Comparison 5: Morbidity: clinical outcomes, Outcome 1: Cardiac events
Comparison 5: Morbidity: clinical outcomes, Outcome 2: Myocardial infarction
Comparison 5: Morbidity: clinical outcomes, Outcome 3: Congestive heart failure
Comparison 5: Morbidity: clinical outcomes, Outcome 4: Cerebrovascular accident (CVA) ‐ stroke
Comparison 5: Morbidity: clinical outcomes, Outcome 5: Rebleeding
Comparison 5: Morbidity: clinical outcomes, Outcome 6: Sepsis/bacteraemia
Comparison 5: Morbidity: clinical outcomes, Outcome 7: Pneumonia
Comparison 5: Morbidity: clinical outcomes, Outcome 8: Infection
Comparison 5: Morbidity: clinical outcomes, Outcome 9: Thromboembolism
Comparison 5: Morbidity: clinical outcomes, Outcome 10: Renal failure
Comparison 5: Morbidity: clinical outcomes, Outcome 11: Mental confusion
Comparison 6: Blood transfusions, Outcome 1: Participants exposed to blood transfusion (all trials)
Comparison 6: Blood transfusions, Outcome 2: Participants exposed to blood transfusion by clinical specialties
Comparison 6: Blood transfusions, Outcome 3: Participants exposed to blood transfusion (by transfusion threshold)
Comparison 6: Blood transfusions, Outcome 4: Participants exposed to blood transfusion by transfusion threshold
Comparison 6: Blood transfusions, Outcome 5: Units of blood transfused
Comparison 7: Morbidity outcomes in participants undergoing cardiac surgery or vascular surgery, and with acute MI, Outcome 1: Myocardial infarction
Comparison 7: Morbidity outcomes in participants undergoing cardiac surgery or vascular surgery, and with acute MI, Outcome 2: Renal failure
Comparison 7: Morbidity outcomes in participants undergoing cardiac surgery or vascular surgery, and with acute MI, Outcome 3: Infection
Comparison 7: Morbidity outcomes in participants undergoing cardiac surgery or vascular surgery, and with acute MI, Outcome 4: Congestive heart failure
Comparison 7: Morbidity outcomes in participants undergoing cardiac surgery or vascular surgery, and with acute MI, Outcome 5: Thromboembolism
Comparison 7: Morbidity outcomes in participants undergoing cardiac surgery or vascular surgery, and with acute MI, Outcome 6: Cerebrovascular accident
| Liberal compared with restrictive transfusion protocols for guiding red blood cell transfusion | ||||||
| Patient or population: adults and children (haemodynamically stable) with potential need for RBC transfusion | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect | №. of participants | Certainty of the evidence | Comments | |
|---|---|---|---|---|---|---|
| Risk with liberal transfusion protocol | Risk with restrictive transfusion protocol | |||||
| Participants exposed to blood transfusion (all studies) | Study population | RR 0.59 | 20,057 | ⊕⊕⊕⊕ | ||
| 815 per 1000 | 481 per 1000 | |||||
| 30‐Day mortality | Study population | RR 0.99 | 16,729 | ⊕⊕⊕⊕ | ||
| 83 per 1000 | 83 per 1000 | |||||
| Myocardial infarction | Study population | RR 1.04 | 14,370 | ⊕⊕⊕⊕ | ||
| 32 per 1000 | 33 per 1000 | |||||
| Congestive heart failure | Study population | RR 0.83 | 7247 | ⊕⊕⊝⊝ | ||
| 35 per 1000 | 29 per 1000 | |||||
| Cerebrovascular accident ‐ stroke | Study population | RR 0.84 | 13,985 | ⊕⊕⊕⊕ | ||
| 17 per 1000 | 14 per 1000 | |||||
| Rebleeding | Study population | RR 0.80 | 3412 | ⊕⊕⊕⊝ | ||
| 158 per 1000 | 126 per 1000 | |||||
| Thromboembolism | Study population | OR 1.11 | 4201 | ⊕⊕⊕⊝ | ||
| 15 per 1000 | 17 per 1000 | |||||
| Infection | Study population | RR 0.97 | 17,104 | ⊕⊕⊕⊕ | ||
| 143 per 1000 | 139 per 1000 | |||||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence. | ||||||
| aWe downgraded once for inconsistency, as there was no consistency in the direction of the effect (despite the relatively low statistical heterogeneity), and we downgraded once for imprecision, as there were very low numbers of events. bDespite relatively low statistical heterogeneity, there was no consistency in the direction of the effect, hence we downgraded once for inconsistency. cDowngraded once for imprecision, as there were few events (and hence a wide CI). | ||||||
| Study ID | Number of participants at baseline | Country/Countries | Number of sites | Setting(s) | Year recruitment started |
|---|---|---|---|---|---|
| Mazer 2017 | 5092 | 19 countriesa | 73 | 73 sites ‐ varied | 2014 |
| Carson 2011 | 2016 | USA, Canada | 47 | 47 sites ‐ varied | 2004 |
| Murphy 2015 | 2003 | UK | 17 | 17 sites ‐ varied | 2009 |
| Holst 2014 | 1005 | Denmark, Sweden, Norway, Finland | 32 | 32 general ICUs | 2011 |
| Jairath 2015 | 936 | UK | 6 | University teaching hospitals | 2012 |
| Villanueva 2013 | 921 | Spain | 1 | General hospital | 2003 |
| Hébert 1999 | 838 | Canada | 25 | Tertiary (22), community ICU (3) | 1994 |
| Koch 2017 | 722 | USA (1), India (1) | 2 | 1 academic affiliated hospital in the USA, a private hospital in India | 2007 |
| Ducrocq 2021 | 668 | France, Spain | 35 | 35 sites ‐ varied | 2016 |
| Lacroix 2007 | 648 | Canada, Belgium, USA, UK | 19 | Tertiary paediatric ICU | 2001 |
| So‐Osman 2013 | 603 | Netherlands | 3 | Varied ‐ university and general hospitals | 2001 |
| Prick 2014 | 519 | Netherlands | 37 | Varied ‐ university and general hospitals | 2004 |
| Hajjar 2010 | 512 | Brazil | 1 | University teaching hospital | 2009 |
| Hoff 2011 | 466 | Denmark | ?? | Oncology centres | 1986 |
| Bracey 1999 | 428 | USA | 1 | University teaching hospital | 1997 |
| Palmieri 2017 | 345 | US (16 sites), Canada (1), New Zealand (1) | 18 | Specialist burn centres | 2010 |
| Tay 2020 | 300 | Canada | 4 | HCT sites | 2011 |
| Bergamin 2017 | 300 | Brazil | 1 | University teaching hospital | 2012 |
| Gregersen 2015 | 284 | Denmark | 1 | University teaching hospital | 2010 |
| Grover 2006 | 260 | UK | 3 | Acute hospitals | Not stated |
| Kola 2020 | 224 | India | 1 | Tertiary hospital | 2015 |
| Parker 2013 | 200 | UK | 1 | General hospital | 2002 |
| de Almeida 2015 | 198 | Brazil | 1 | Tertiary oncology university hospital | 2012 |
| Fan 2014 | 192 | China | 1 | University teaching hospital | 2011 |
| Akyildiz 2018 | 180 | Turkey | 1 | University teaching hospital | 2014 |
| Yakymenko 2018 | 133 | Denmark | 1 | University teaching hospital | 2010 |
| Lotke 1999 | 127 | USA | 1 | University teaching hospital | Not stated |
| Foss 2009 | 120 | Denmark | 1 | University teaching hospital | 2004 |
| Carson 2013 | 110 | USA | 8 | 8 sites ‐ varied | 2010 |
| Walsh 2013 | 100 | UK | 6 | Varied ‐ university and general hospitals | 2009 |
| Bush 1997 | 99 | USA | 1 | University teaching hospital | 1995 |
| DeZern 2016 | 89 | USA | 1 | Tertiary referral centre for oncology | 2014 |
| Carson 1998 | 84 | USA (3), UK (1) | 4 | University teaching hospitals | 1996 |
| Laine 2018 | 80 | Finland | 1 | University teaching hospital | 2014 |
| Hébert 1995 | 69 | Canada | 5 | Tertiary hospitals | 1993 |
| Nielsen 2014 | 66 | Denmark | 2 | University teaching hospital and general hospital | 2009 |
| Gillies 2020 | 62 | UK | 1 | University teaching hospital | 2017 |
| Webert 2008 | 60 | Canada | 4 | Tertiary oncology centres | 2003 |
| Møller 2019 | 58 | Denmark | 1 | General hospital | 2015 |
| Shehata 2012 | 50 | Canada | 1 | University teaching hospital | 2007 |
| Blair 1986 | 50 | UK | 1 | University teaching hospital | Not stated |
| Gobatto 2019 | 47 | Brazil | 1 | University teaching hospital | 2014 |
| Cooper 2011 | 45 | USA | 2 | Veterans' Affairs hospital centres | 2003 |
| Johnson 1992 | 39 | USA | 1 | University teaching hospital | Not stated |
| Stanworth 2020 | 38 | UK, Australia, New Zealand | 12 | 12 sites ‐ varied | 2015 |
| Topley 1956 | 22 | UK | 1 | 'Accident hospital' | Not stated |
| Januarysen 2020 | 19 | Netherlands | 3 | 1 university hospital, 2 general hospitals | 2002 |
| Robitaille 2013 | 6 | Canada | 1 | Not identified | 2009 |
| aMazer 2017 (TRICS‐III): majority of sites in USA; sites also in Australia, Brazil, Canada, China, Colombia, Denmark, Egypt, Germany, Greece, India, Israel, Malaysia, New Zealand, Romania, Singapore, South Africa, Spain, and Switzerland. | |||||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1.1 30‐Day mortality Show forest plot | 31 | 16729 | Risk Ratio (M‐H, Random, 95% CI) | 0.99 [0.86, 1.15] |
| 1.2 30‐Day mortality subgroup by restrictive haemoglobin level Show forest plot | 31 | 16729 | Risk Ratio (M‐H, Random, 95% CI) | 0.99 [0.86, 1.14] |
| 1.2.1 Restrictive 7.0 g/dL to 7.5 g/dL | 15 | 11572 | Risk Ratio (M‐H, Random, 95% CI) | 1.00 [0.83, 1.19] |
| 1.2.2 Restrictive < 8.0 g/dL to 9.0 g/dL | 16 | 5157 | Risk Ratio (M‐H, Random, 95% CI) | 0.97 [0.75, 1.24] |
| 1.3 30‐Day mortality subgroup analysis by clinical specialties Show forest plot | 31 | 16729 | Risk Ratio (M‐H, Random, 95% CI) | 0.99 [0.86, 1.14] |
| 1.3.1 Cardiac surgery | 4 | 7441 | Risk Ratio (M‐H, Random, 95% CI) | 0.99 [0.74, 1.33] |
| 1.3.2 Orthopaedic surgery | 8 | 3111 | Risk Ratio (M‐H, Random, 95% CI) | 1.16 [0.75, 1.79] |
| 1.3.3 Vascular | 2 | 157 | Risk Ratio (M‐H, Random, 95% CI) | 0.98 [0.30, 3.25] |
| 1.3.4 Acute blood loss/trauma | 3 | 1522 | Risk Ratio (M‐H, Random, 95% CI) | 0.65 [0.43, 0.97] |
| 1.3.5 Critical care | 9 | 3529 | Risk Ratio (M‐H, Random, 95% CI) | 1.06 [0.85, 1.32] |
| 1.3.6 Acute myocardial infarction | 3 | 820 | Risk Ratio (M‐H, Random, 95% CI) | 1.61 [0.38, 6.88] |
| 1.3.7 Haematological malignancies | 2 | 149 | Risk Ratio (M‐H, Random, 95% CI) | 0.37 [0.07, 1.95] |
| 1.4 30‐Day mortality by clinical specialties: myocardial infarction vs all others Show forest plot | 31 | 16729 | Risk Ratio (M‐H, Random, 95% CI) | 0.99 [0.86, 1.14] |
| 1.4.1 Myocardial infarction | 3 | 820 | Risk Ratio (M‐H, Random, 95% CI) | 1.61 [0.38, 6.88] |
| 1.4.2 All but myocardial infarction | 28 | 15909 | Risk Ratio (M‐H, Random, 95% CI) | 0.99 [0.86, 1.15] |
| 1.5 Mortality by cardiac surgery, vascular surgery, myocardial infarction, and all others Show forest plot | 31 | 16729 | Risk Ratio (M‐H, Random, 95% CI) | 0.99 [0.86, 1.14] |
| 1.5.1 Cardiac surgery | 4 | 7441 | Risk Ratio (M‐H, Random, 95% CI) | 0.99 [0.74, 1.33] |
| 1.5.2 Myocardial infarction | 3 | 820 | Risk Ratio (M‐H, Random, 95% CI) | 1.61 [0.38, 6.88] |
| 1.5.3 Vascular surgery | 2 | 157 | Risk Ratio (M‐H, Random, 95% CI) | 0.98 [0.30, 3.25] |
| 1.5.4 Others | 22 | 8311 | Risk Ratio (M‐H, Random, 95% CI) | 0.99 [0.83, 1.19] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 2.1 30‐Day mortality Show forest plot | 31 | 16729 | Risk Ratio (M‐H, Random, 95% CI) | 0.99 [0.86, 1.15] |
| 2.1.1 Prospectively registered trials | 18 | 12932 | Risk Ratio (M‐H, Random, 95% CI) | 1.08 [0.89, 1.31] |
| 2.1.2 Trials without prospective registration | 13 | 3797 | Risk Ratio (M‐H, Random, 95% CI) | 0.81 [0.66, 1.00] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 3.1 30‐Day mortality Show forest plot | 31 | 16729 | Risk Ratio (M‐H, Random, 95% CI) | 0.99 [0.86, 1.15] |
| 3.1.1 Low risk of bias | 26 | 15764 | Risk Ratio (M‐H, Random, 95% CI) | 1.01 [0.87, 1.18] |
| 3.1.2 Unclear or high risk of bias | 5 | 965 | Risk Ratio (M‐H, Random, 95% CI) | 0.84 [0.51, 1.39] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 4.1 Hospital mortality Show forest plot | 15 | 6597 | Risk Ratio (M‐H, Random, 95% CI) | 0.86 [0.72, 1.03] |
| 4.2 90‐Day mortality Show forest plot | 7 | 4143 | Risk Ratio (M‐H, Random, 95% CI) | 1.13 [1.02, 1.25] |
| 4.3 6‐Month mortality Show forest plot | 2 | 4702 | Risk Ratio (M‐H, Random, 95% CI) | 0.98 [0.79, 1.22] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 5.1 Cardiac events Show forest plot | 11 | 5577 | Risk Ratio (M‐H, Random, 95% CI) | 1.03 [0.80, 1.32] |
| 5.2 Myocardial infarction Show forest plot | 23 | 14370 | Risk Ratio (M‐H, Random, 95% CI) | 1.04 [0.87, 1.24] |
| 5.3 Congestive heart failure Show forest plot | 16 | 7247 | Risk Ratio (M‐H, Random, 95% CI) | 0.83 [0.53, 1.29] |
| 5.4 Cerebrovascular accident (CVA) ‐ stroke Show forest plot | 19 | 13985 | Risk Ratio (M‐H, Random, 95% CI) | 0.84 [0.64, 1.09] |
| 5.5 Rebleeding Show forest plot | 8 | 3412 | Risk Ratio (M‐H, Random, 95% CI) | 0.80 [0.59, 1.09] |
| 5.6 Sepsis/bacteraemia Show forest plot | 9 | 4352 | Risk Ratio (M‐H, Random, 95% CI) | 1.06 [0.86, 1.30] |
| 5.7 Pneumonia Show forest plot | 16 | 6666 | Risk Ratio (M‐H, Random, 95% CI) | 0.97 [0.84, 1.13] |
| 5.8 Infection Show forest plot | 25 | 17104 | Risk Ratio (M‐H, Random, 95% CI) | 0.97 [0.88, 1.07] |
| 5.9 Thromboembolism Show forest plot | 13 | 4201 | Peto Odds Ratio (Peto, Fixed, 95% CI) | 1.11 [0.65, 1.88] |
| 5.10 Renal failure Show forest plot | 15 | 12531 | Risk Ratio (M‐H, Random, 95% CI) | 1.03 [0.92, 1.16] |
| 5.11 Mental confusion Show forest plot | 9 | 6442 | Risk Ratio (M‐H, Random, 95% CI) | 1.11 [0.88, 1.40] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 6.1 Participants exposed to blood transfusion (all trials) Show forest plot | 42 | 20057 | Risk Ratio (M‐H, Random, 95% CI) | 0.59 [0.53, 0.66] |
| 6.2 Participants exposed to blood transfusion by clinical specialties Show forest plot | 41 | 19977 | Risk Ratio (M‐H, Random, 95% CI) | 0.59 [0.53, 0.66] |
| 6.2.1 Cardiac surgery | 7 | 8598 | Risk Ratio (M‐H, Random, 95% CI) | 0.69 [0.66, 0.73] |
| 6.2.2 Orthopaedic surgery | 11 | 3969 | Risk Ratio (M‐H, Random, 95% CI) | 0.49 [0.38, 0.65] |
| 6.2.3 Vascular surgery | 2 | 157 | Risk Ratio (M‐H, Random, 95% CI) | 0.79 [0.57, 1.08] |
| 6.2.4 Acute blood loss/trauma | 5 | 2416 | Risk Ratio (M‐H, Random, 95% CI) | 0.39 [0.23, 0.67] |
| 6.2.5 Critical care | 9 | 3529 | Risk Ratio (M‐H, Random, 95% CI) | 0.66 [0.57, 0.77] |
| 6.2.6 Acute myocardial infarction | 3 | 821 | Risk Ratio (M‐H, Random, 95% CI) | 0.38 [0.28, 0.53] |
| 6.2.7 Haematological malignancies | 4 | 487 | Risk Ratio (M‐H, Random, 95% CI) | 0.88 [0.61, 1.26] |
| 6.3 Participants exposed to blood transfusion (by transfusion threshold) Show forest plot | 33 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 6.3.1 Difference between liberal and restrictive haemoglobin thresholds ≥ 2.0 g/dL | 27 | 15072 | Risk Ratio (M‐H, Random, 95% CI) | 0.57 [0.50, 0.64] |
| 6.3.2 Difference between liberal and restrictive haemoglobin thresholds < 2.0 g/dL | 6 | 2966 | Risk Ratio (M‐H, Random, 95% CI) | 0.80 [0.63, 1.02] |
| 6.4 Participants exposed to blood transfusion by transfusion threshold Show forest plot | 36 | 17954 | Risk Ratio (M‐H, Random, 95% CI) | 0.57 [0.51, 0.64] |
| 6.4.1 Restrictive 7.0 g/dL to 7.5 g/dL | 17 | 11919 | Risk Ratio (M‐H, Random, 95% CI) | 0.55 [0.48, 0.64] |
| 6.4.2 Restrictive < 8.0 g/dL to 9.0 g/dL | 19 | 6035 | Risk Ratio (M‐H, Random, 95% CI) | 0.59 [0.48, 0.72] |
| 6.5 Units of blood transfused Show forest plot | 17 | 6253 | Mean Difference (IV, Random, 95% CI) | ‐1.21 [‐1.67, ‐0.75] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 7.1 Myocardial infarction Show forest plot | 8 | 8219 | Odds Ratio (M‐H, Fixed, 95% CI) | 1.01 [0.81, 1.26] |
| 7.2 Renal failure Show forest plot | 7 | 9198 | Odds Ratio (M‐H, Fixed, 95% CI) | 1.07 [0.89, 1.28] |
| 7.3 Infection Show forest plot | 8 | 9219 | Risk Ratio (M‐H, Random, 95% CI) | 1.00 [0.79, 1.28] |
| 7.4 Congestive heart failure Show forest plot | 4 | 858 | Risk Ratio (M‐H, Random, 95% CI) | 0.77 [0.24, 2.43] |
| 7.5 Thromboembolism Show forest plot | 3 | 239 | Risk Ratio (M‐H, Random, 95% CI) | 1.02 [0.11, 9.55] |
| 7.6 Cerebrovascular accident Show forest plot | 4 | 905 | Risk Ratio (M‐H, Random, 95% CI) | 0.98 [0.22, 4.26] |
