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Effectiveness of Enhanced Performance Feedback on Appropriate Use of Blood Transfusions: A Comparison of 2 Cluster Randomized Trials
Stanworth SJ, Walwyn R, Grant-Casey J, Hartley S, Moreau L, Lorencatto F, Francis J, Gould N, Swart N, Rowley M, et al
JAMA network open. 2022;5(2):e220364
Abstract
IMPORTANCE Auditing and feedback are frequently used to improve patient care. However, it remains unclear how to optimize feedback effectiveness for the appropriate use of treatments such as blood transfusion, a common but costly procedure that is more often overused than underused. OBJECTIVE To evaluate 2 theoretically informed feedback interventions to improve the appropriate use of blood transfusions. DESIGN, SETTING, AND PARTICIPANTS Two sequential, linked 2 × 2 cluster randomized trials were performed in hospitals in the UK participating in national audits of transfusion for perioperative anemia and management of hematological disorders. Data were collected for a surgical trial from October 1, 2014, to October 31, 2016, with follow-up completed on October 31, 2016. Data were collected for a hematological trial through follow-up from July 1, 2015, to June 30, 2017. Trial data were analyzed from November 1, 2016, to June 1, 2019. INTERVENTIONS Hospitals were randomized to standard content or enhanced content to improve feedback clarity and usability and to standard support or enhanced support for staff to act on feedback. MAIN OUTCOMES AND MEASURES The primary end point was appropriateness of transfusions audited at 12 months. Secondary end points included volume of transfusions (aiming for reductions at patient and cluster levels) and transfusion-related adverse events and reactions. RESULTS One hundred thirty-five of 152 eligible clusters participated in the surgical audit (2714 patients; mean [SD] age, 74.9 [14.0] years; 1809 women [66.7%]), and 134 of 141 participated in the hematological audit (4439 patients; median age, 72.0 [IQR, 64.0-80.0] years; 2641 men [59.5%]). Fifty-seven of 69 clusters (82.6%) in the surgical audit randomized to enhanced content downloaded reports compared with 52 of 66 clusters (78.8%) randomized to standard reports. Fifty-nine of 68 clusters (86.8%) randomized to enhanced support logged onto the toolkit. The proportion of patients with appropriate transfusions was 0.184 for standard content and 0.176 for enhanced content (adjusted odds ratio [OR], 0.91 [97.5% CI, 0.61-1.36]) and 0.181 for standard support and 0.180 for enhanced support (adjusted OR, 1.05 [97.5% CI, 0.68-1.61]). For the hematological audit, 53 of 66 clusters (80.3%) randomized to enhanced content downloaded the reports compared with 53 of 68 clusters (77.9%) randomized to standard content. Forty-nine of 67 clusters sites (73.1%) assigned to enhanced support logged into the toolkit at least once. The proportion of patients with appropriate transfusions was 0.744 for standard content and 0.714 for enhanced content (adjusted OR, 0.81 [97.5% CI, 0.56-1.12]), and 0.739 for standard support and 0.721 for enhanced support (adjusted OR, 0.96 [97.5% CI, 0.67-1.38]). CONCLUSIONS AND RELEVANCE This comparison of cluster randomized trials found that interventions to improve feedback usability and guide local action were no more effective than standard feedback in increasing the appropriate use of blood transfusions. Auditing and feedback delivered at scale is a complex and costly program; therefore, effective responses may depend on developing robust local quality improvement arrangements, which can be evaluated using rigorous experimental designs embedded within national programs. TRIAL REGISTRATION isrctn.org Identifier: ISRCTN15490813.
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Do liberal thresholds for red cell transfusion result in improved quality of life for patients undergoing intensive chemotherapy for acute myeloid leukemia? A randomized cross over feasibility study
Morton S, Sekhar M, Smethurst H, Mora A, Hodge RL, Hudson CL, Parsons J, Hopkins V, Stanworth SJ
Haematologica. 2022
Abstract
Not available.
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Transfusion thresholds for guiding red blood cell transfusion
Carson JL, Stanworth SJ, Dennis JA, Trivella M, Roubinian N, Fergusson DA, Triulzi D, Dorée C, Hébert PC
The Cochrane database of systematic reviews. 2021;12:Cd002042
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Editor's Choice
Abstract
BACKGROUND The optimal haemoglobin threshold for use of red blood cell (RBC) transfusions in anaemic patients remains an active field of research. Blood is a scarce resource, and in some countries, transfusions are less safe than in others because of inadequate testing for viral pathogens. If a liberal transfusion policy does not improve clinical outcomes, or if it is equivalent, then adopting a more restrictive approach could be recognised as the standard of care. OBJECTIVES The aim of this review update was to compare 30-day mortality and other clinical outcomes for participants randomised to restrictive versus liberal red blood cell (RBC) transfusion thresholds (triggers) for all clinical conditions. The restrictive transfusion threshold uses a lower haemoglobin concentration as a threshold for transfusion (most commonly, 7.0 g/dL to 8.0 g/dL), and the liberal transfusion threshold uses a higher haemoglobin concentration as a threshold for transfusion (most commonly, 9.0 g/dL to 10.0 g/dL). SEARCH METHODS We identified trials through updated searches: CENTRAL (2020, Issue 11), MEDLINE (1946 to November 2020), Embase (1974 to November 2020), Transfusion Evidence Library (1950 to November 2020), Web of Science Conference Proceedings Citation Index (1990 to November 2020), and trial registries (November 2020). We checked the reference lists of other published reviews and relevant papers to identify additional trials. We were aware of one trial identified in earlier searching that was in the process of being published (in February 2021), and we were able to include it before this review was finalised. SELECTION CRITERIA We included randomised trials of surgical or medical participants that recruited adults or children, or both. We excluded studies that focused on neonates. Eligible trials assigned intervention groups on the basis of different transfusion schedules or thresholds or 'triggers'. These thresholds would be defined by a haemoglobin (Hb) or haematocrit (Hct) concentration below which an RBC transfusion would be administered; the haemoglobin concentration remains the most commonly applied marker of the need for RBC transfusion in clinical practice. We included trials in which investigators had allocated participants to higher thresholds or more liberal transfusion strategies compared to more restrictive ones, which might include no transfusion. As in previous versions of this review, we did not exclude unregistered trials published after 2010 (as per the policy of the Cochrane Injuries Group, 2015), however, we did conduct analyses to consider the differential impact of results of trials for which prospective registration could not be confirmed. DATA COLLECTION AND ANALYSIS We identified trials for inclusion and extracted data using Cochrane methods. We pooled risk ratios of clinical outcomes across trials using a random-effects model. Two review authors independently extracted data and assessed risk of bias. We conducted predefined analyses by clinical subgroups. We defined participants randomly allocated to the lower transfusion threshold as being in the 'restrictive transfusion' group and those randomly allocated to the higher transfusion threshold as being in the 'liberal transfusion' group. MAIN RESULTS A total of 48 trials, involving data from 21,433 participants (at baseline), across a range of clinical contexts (e.g. orthopaedic, cardiac, or vascular surgery; critical care; acute blood loss (including gastrointestinal bleeding); acute coronary syndrome; cancer; leukaemia; haematological malignancies), met the eligibility criteria. The haemoglobin concentration used to define the restrictive transfusion group in most trials (36) was between 7.0 g/dL and 8.0 g/dL. Most trials included only adults; three trials focused on children. The included studies were generally at low risk of bias for key domains including allocation concealment and incomplete outcome data. Restrictive transfusion strategies reduced the risk of receiving at least one RBC transfusion by 41% across a broad range of clinical contexts (risk ratio (RR) 0.59, 95% confidence interval (CI) 0.53 to 0.66; 42 studies, 20,057 participants; high-quality evidence), with a large amount of heterogeneity between trials (I² = 96%). Overall, restrictive transfusion strategies did not increase or decrease the risk of 30-day mortality compared with liberal transfusion strategies (RR 0.99, 95% CI 0.86 to 1.15; 31 studies, 16,729 participants; I² = 30%; moderate-quality evidence) or any of the other outcomes assessed (i.e. cardiac events (low-quality evidence), myocardial infarction, stroke, thromboembolism (all high-quality evidence)). High-quality evidence shows that the liberal transfusion threshold did not affect the risk of infection (pneumonia, wound infection, or bacteraemia). Transfusion-specific reactions are uncommon and were inconsistently reported within trials. We noted less certainty in the strength of evidence to support the safety of restrictive transfusion thresholds for the following predefined clinical subgroups: myocardial infarction, vascular surgery, haematological malignancies, and chronic bone-marrow disorders. AUTHORS' CONCLUSIONS Transfusion at a restrictive haemoglobin concentration decreased the proportion of people exposed to RBC transfusion by 41% across a broad range of clinical contexts. Across all trials, no evidence suggests that a restrictive transfusion strategy impacted 30-day mortality, mortality at other time points, or morbidity (i.e. cardiac events, myocardial infarction, stroke, pneumonia, thromboembolism, infection) compared with a liberal transfusion strategy. Despite including 17 more randomised trials (and 8846 participants), data remain insufficient to inform the safety of transfusion policies in important and selected clinical contexts, such as myocardial infarction, chronic cardiovascular disease, neurological injury or traumatic brain injury, stroke, thrombocytopenia, and cancer or haematological malignancies, including chronic bone marrow failure. Further work is needed to improve our understanding of outcomes other than mortality. Most trials compared only two separate thresholds for haemoglobin concentration, which may not identify the actual optimal threshold for transfusion in a particular patient. Haemoglobin concentration may not be the most informative marker of the need for transfusion in individual patients with different degrees of physiological adaptation to anaemia. Notwithstanding these issues, overall findings provide good evidence that transfusions with allogeneic RBCs can be avoided in most patients with haemoglobin thresholds between the range of 7.0 g/dL and 8.0 g/dL. Some patient subgroups might benefit from RBCs to maintain higher haemoglobin concentrations; research efforts should focus on these clinical contexts.
PICO Summary
Population
Adults and children across a range of clinical contexts including surgery (48 studies, n= 21,433).
Intervention
Restrictive red blood cell (RBC) transfusion threshold strategy.
Comparison
Liberal RBC transfusion threshold strategy.
Outcome
Restrictive transfusion strategies reduced the risk of receiving at least one RBC transfusion by 41% across a broad range of clinical contexts (risk ratio (RR) 0.59, 95% confidence interval (CI) 0.53 to 0.66; 42 studies, 20,057 participants; high-quality evidence), with a large amount of heterogeneity between trials (I² = 96%). Overall, restrictive transfusion strategies did not increase or decrease the risk of 30-day mortality compared with liberal transfusion strategies (RR 0.99, 95% CI 0.86 to 1.15; 31 studies, 16,729 participants; I² = 30%; moderate-quality evidence) or any of the other outcomes assessed (i.e. cardiac events (low-quality evidence), myocardial infarction, stroke, thromboembolism (all high-quality evidence)). High-quality evidence showed that the liberal transfusion threshold did not affect the risk of infection (pneumonia, wound infection, or bacteraemia). Transfusion-specific reactions were uncommon and were inconsistently reported within trials.
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Red cell transfusion in outpatients with myelodysplastic syndromes: a feasibility and exploratory randomised trial
Stanworth SJ, Killick S, McQuilten ZK, Karakantza M, Weinkove R, Smethurst H, Pankhurst LA, Hodge RL, Hopkins V, Thomas HL, et al
British journal of haematology. 2020
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Editor's Choice
Abstract
Optimal red cell transfusion support in myelodysplastic syndromes (MDS) has not been tested and established. The aim of this study was to demonstrate feasibility of recruitment and follow-up in an outpatient setting with an exploratory assessment of quality of life (QoL) outcomes (EORTC QLQ-C30 and EQ-5D-5L). We randomised MDS patients to standardised transfusion algorithms comparing current restrictive transfusion thresholds (80 g/l, to maintain haemoglobin 85-100 g/l) with liberal thresholds (105 g/l, maintaining 110-125 g/l). The primary outcomes were measures of compliance to transfusion thresholds. Altogether 38 patients were randomised (n = 20 restrictive; n = 18 liberal) from 12 participating sites in UK, Australia and New Zealand. The compliance proportion for the intention-to-treat population was 86% (95% confidence interval 75-94%) and 99% (95-100%) for restrictive and liberal arms respectively. Mean pre-transfusion haemoglobin concentrations for restrictive and liberal arms were 80 g/l (SD6) and 97 g/l (SD7). The total number of red cell units transfused on study was 82 in the restrictive and 192 in the liberal arm. In an exploratory analysis, the five main QoL domains were improved for participants in the liberal compared to restrictive arm. Our findings support the feasibility and need for a definitive trial to evaluate the effect of different red cell transfusion thresholds on patient-centred outcomes.
PICO Summary
Population
Patients with myelodysplastic syndrome, (n=38).
Intervention
Restrictive transfusion threshold (80 g/l, to maintain haemoglobin 85-100 g/l), (n=20).
Comparison
Liberal transfusion threshold (105 g/l, to maintain haemoglobin 110-125 g/l), (n=18).
Outcome
The compliance proportion for the intention-to-treat population was 86% and 99% for restrictive and liberal arms respectively. Mean pre-transfusion haemoglobin concentrations for restrictive and liberal arms were 80 g/l (SD6) and 97 g/l (SD7). The total number of red cell units transfused on study was 82 in the restrictive and 192 in the liberal arm. In an exploratory analysis, the five main QoL domains were improved for participants in the liberal compared to restrictive arm.
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Transfusion of red blood cells stored for shorter versus longer duration for all conditions
Shah A, Brunskill SJ, Desborough MJ, Doree C, Trivella M, Stanworth SJ
The Cochrane Database of Systematic Reviews. 2018;12:CD010801.
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BACKGROUND Red blood cell (RBC) transfusion is a common treatment for anaemia in many conditions. The safety and efficacy of transfusing RBC units that have been stored for different durations before a transfusion is a current concern. The duration of storage for a RBC unit can be up to 42 days. If evidence from randomised controlled trials (RCT) were to indicate that clinical outcomes are affected by storage duration, the implications for inventory management and clinical practice would be significant. OBJECTIVES To assess the effects of using red blood cells (RBCs) stored for a shorter versus a longer duration, or versus RBCs stored for standard practice duration, in people requiring a RBC transfusion. SEARCH METHODS We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, CINAHL, PubMed (for epublications), LILACS, Transfusion Evidence Library, Web of Science CPCI-S and four international clinical trial registries on 20 November 2017. SELECTION CRITERIA We included RCTs that compared transfusion of RBCs of shorter versus longer storage duration, or versus standard practice storage duration. DATA COLLECTION AND ANALYSIS We used standard Cochrane methods. MAIN RESULTS We included 22 trials (42,835 participants) in this review.The GRADE quality of evidence ranged from very low to moderate for our primary outcome of in-hospital and short-term mortality reported at different time points.Transfusion of RBCs of shorter versus longer storage duration Eleven trials (2249 participants) compared transfusion of RBCs of shorter versus longer storage duration. Two trials enrolled low birth weight neonates, two enrolled children with severe anaemia secondary to malaria or sickle cell disease, and eight enrolled adults across a range of clinical settings (intensive care, cardiac surgery, major elective surgery, hospitalised in-patients, haematology outpatients). We judged only two trials to be at low risk of bias across all domains; most trials had an unclear risk for multiple domains.Transfusion of RBCs of shorter versus longer storage duration probably leads to little or no difference in mortality at seven-day follow-up (risk ratio (RR) 1.42, 95% confidence interval (CI) 0.66 to 3.06; 1 trial, 3098 participants; moderate quality evidence) or 30-day follow-up (RR 0.85, 95%CI 0.50 to 1.45; 2 trials, 1121 participants; moderate quality evidence) in adults undergoing major elective cardiac or non-cardiac surgery.For neonates, no studies reported on the primary outcome of in-hospital or short-term mortality. At 40 weeks gestational age, the effect of RBCs of shorter versus longer storage duration on the risk of death was uncertain, as the quality of evidence is very low (RR 0.90, 95% CI 0.41 to 1.85; 1 trial, 52 participants).The effect of RBCs of shorter versus longer storage duration on the risk of death in children with severe anaemia was also uncertain within 24 hours of transfusion (RR 1.50, 95% CI 0.43 to 5.25; 2 trials, 364 participants; very low quality evidence), or at 30-day follow-up (RR 1.40, 95% CI 0.45 to 4.31; 1 trial, 290 participants; low quality evidence).Only one trial, in children with severe anaemia (290 participants), reported adverse transfusion reactions. Only one child in each arm experienced an adverse reaction within 24 hours of transfusion.Transfusion of RBCs of shorter versus standard practice storage duration Eleven trials (40,588 participants) compared transfusion of RBCs of shorter versus standard practice storage duration. Three trials enrolled critically ill term neonates; two of these enrolled very low birth weight neonates. There were no trials in children. Eight trials enrolled critically ill and non-critically ill adults, with most being hospitalised. We judged four trials to be at low risk of bias across all domains with the others having an unclear risk of bias across multiple domains.Transfusion of RBCs of shorter versus standard practice storage duration probably leads to little or no difference in adult in-hospital mortality (RR 1.05, 95% CI 0.97 to 1.14; 4 trials, 25,704 participants; moderate quality evidence), ICU mortality (RR 1.06, 95% CI 0.98 to 1.15; 3 trials, 13,066 participants; moderate quality evidence), or 30-day mortality (RR 1.04, 95% CI 0.96 to 1.13; 4 trials, 7510 participants;moderate quality evidence).Two of the three trials that enrolled neonates reported that there were no adverse transfusion reactions. One trial reported an isolated case of cytomegalovirus infection in participants assigned to the standard practice storage duration group. Two trials in critically ill adults reported data on transfusion reactions: one observed no difference in acute transfusion reactions between arms (RR 0.67, 95% CI 0.19 to 2.36, 2413 participants), but the other observed more febrile nonhaemolytic reactions in the shorter storage duration arm (RR 1.48, 95% CI 1.13 to 1.95, 4919 participants).Trial sequential analysis showed that we may now have sufficient evidence to reject a 5% relative risk increase or decrease of death within 30 days when transfusing RBCs of shorter versus longer storage duration across all patient groups. AUTHORS' CONCLUSIONS The effect of storage duration on clinically important outcomes has now been investigated in large, high quality RCTs, predominantly in adults. There appears to be no evidence of an effect on mortality that is related to length of storage of transfused RBCs. However, the quality of evidence in neonates and children is low. The current practice in blood banks of using the oldest available RBCs can be continued safely. Additional RCTs are not required, but research using alternative study designs, should focus on particular subgroups (e.g. those requiring multiple RBC units) and on factors affecting RBC quality.
PICO Summary
Population
Adults, children, and neonates requiring a red blood cell (RBC) transfusion (22 randomised controlled trials, n= 42,835).
Intervention
Transfusion of RBCs of shorter storage duration.
Comparison
Transfusion of RBCs of longer storage duration; Standard practice storage duration.
Outcome
Transfusion of RBCs of shorter vs. longer storage duration (11 trials, n= 2,249) probably led to little or no difference in mortality at seven-day follow-up (risk ratio (RR) 1.42, 95% confidence interval (CI) 0.66 to 3.06; 1 trial, n= 3,098) or 30-day follow-up (RR 0.85, 95%CI 0.50 to 1.45; 2 trials, n= 1,121) in adults undergoing major elective cardiac or non-cardiac surgery. At 40 weeks gestational age, the effect on the risk of death was uncertain (RR 0.90, 95% CI 0.41 to 1.85; 1 trial, n= 52). The effect of RBCs of shorter vs. longer storage duration on the risk of death in children with severe anaemia was also uncertain within 24 hours of transfusion (RR 1.50, 95% CI 0.43 to 5.25; 2 trials, n= 364), or at 30-day follow-up (RR 1.40, 95% CI 0.45 to 4.31; 1 trial, n= 290). Only one trial, in children with severe anaemia (n= 290), reported adverse transfusion reactions. Only one child in each arm experienced an adverse reaction within 24 hours of transfusion. Transfusion of RBCs of shorter vs. standard practice storage duration (11 trials, n= 40,588) probably led to little or no difference in adult in-hospital mortality (RR 1.05, 95% CI 0.97 to 1.14; 4 trials, n= 25,704), ICU mortality (RR 1.06, 95% CI 0.98 to 1.15; 3 trials, n= 13,066), or 30-day mortality (RR 1.04, 95% CI 0.96 to 1.13; 4 trials, n= 7,510). Two of the three trials that enrolled neonates reported that there were no adverse transfusion reactions. One trial reported an isolated case of cytomegalovirus infection in participants assigned to the standard practice storage duration group. Two trials in critically ill adults reported data on transfusion reactions: one observed no difference in acute transfusion reactions between arms (RR 0.67, 95% CI 0.19 to 2.36, n= 2,413), but the other observed more febrile non-haemolytic reactions in the shorter storage duration arm (RR 1.48, 95% CI 1.13 to 1.95, n= 4,919). Trial sequential analysis showed that we may now have sufficient evidence to reject a 5% relative risk increase or decrease of death within 30 days when transfusing RBCs of shorter vs. longer storage duration across all patient groups.
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Effect of restrictive versus liberal red cell transfusion strategies on haemostasis: systematic review and meta-analysis
Desborough MJ, Colman KS, Prick BW, Duvekot JJ, Sweeney C, Odutayo A, Jairath V, Doree C, Trivella M, Hopewell S, et al
Thrombosis and Haemostasis. 2017;117((5):):889-898
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.
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Effect of restrictive versus liberal transfusion strategies on outcomes in patients with cardiovascular disease in a non-cardiac surgery setting: systematic review and meta-analysis
Docherty AB, O'Donnell R, Brunskill S, Trivella M, Doree C, Holst L, Parker M, Gregersen M, Pinheiro de Almeida J, Walsh TS, et al
Bmj.. 2016;352:i1351.
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Editor's Choice
Abstract
OBJECTIVE To compare patient outcomes of restrictive versus liberal blood transfusion strategies in patients with cardiovascular disease not undergoing cardiac surgery. DESIGN Systematic review and meta-analysis. DATA SOURCES Randomised controlled trials involving a threshold for red blood cell transfusion in hospital. We searched (to 2 November 2015) CENTRAL, Medline, Embase, CINAHL, PubMed, LILACS, NHSBT Transfusion Evidence Library, ClinicalTrials.gov, WHO International Clinical Trials Registry Platform, ISRCTN Register, and EU Clinical Trials Register. Authors were contacted for data whenever possible. TRIAL SELECTION Published and unpublished randomised controlled trials comparing a restrictive with liberal transfusion threshold and that included patients with cardiovascular disease. DATA EXTRACTION AND SYNTHESIS Data extraction was completed in duplicate. Risk of bias was assessed using Cochrane methods. Relative risk ratios with 95% confidence intervals were presented in all meta-analyses. Mantel-Haenszel random effects models were used to pool risk ratios. MAIN OUTCOME MEASURES 30 day mortality, and cardiovascular events. RESULTS 41 trials were identified; of these, seven included data on patients with cardiovascular disease. Data from a further four trials enrolling patients with cardiovascular disease were obtained from the authors. In total, 11 trials enrolling patients with cardiovascular disease (n=3033) were included for meta-analysis (restrictive transfusion, n=1514 patients; liberal transfusion, n=1519). The pooled risk ratio for the association between transfusion thresholds and 30 day mortality was 1.15 (95% confidence interval 0.88 to 1.50, P=0.50), with little heterogeneity (I(2)=14%). The risk of acute coronary syndrome in patients managed with restrictive compared with liberal transfusion was increased (nine trials; risk ratio 1.78, 95% confidence interval 1.18 to 2.70, P=0.01, I(2)=0%). CONCLUSIONS The results show that it may not be safe to use a restrictive transfusion threshold of less than 80 g/L in patients with ongoing acute coronary syndrome or chronic cardiovascular disease. Effects on mortality and other outcomes are uncertain. These data support the use of a more liberal transfusion threshold (>80 g/L) for patients with both acute and chronic cardiovascular disease until adequately powered high quality randomised trials have been undertaken in patients with cardiovascular disease. REGISTRATION PROSPERO CRD42014014251.Copyright Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
PICO Summary
Population
Patients with cardiovascular disease not undergoing cardiac surgery (11 randomised controlled trials, n= 3,033).
Intervention
Restrictive transfusion strategy (n= 1,514).
Comparison
Liberal transfusion strategy (n= 1,519).
Outcome
The pooled risk ratio for the association between transfusion thresholds and 30-day mortality was 1.15 (95% confidence interval (CI): 0.88 to 1.50), with little heterogeneity (I2= 14%). The risk of acute coronary syndrome in patients managed with restrictive compared with liberal transfusion was increased (nine trials; risk ratio: 1.78, 95% CI: 1.18 to 2.70, I2= 0%).
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Transfusion thresholds and other strategies for guiding allogeneic red blood cell transfusion
Carson JL, Stanworth SJ, Roubinian N, Fergusson DA, Triulzi D, Doree C, Hebert PC
The Cochrane Database of Systematic Reviews. 2016;((10)):CD002042.
Abstract
BACKGROUND There is considerable uncertainty regarding the optimal haemoglobin threshold for the use of red blood cell (RBC) transfusions in anaemic patients. Blood is a scarce resource, and in some countries, transfusions are less safe than others because of a lack of testing for viral pathogens. Therefore, reducing the number and volume of transfusions would benefit patients. OBJECTIVES The aim of this review was to compare 30-day mortality and other clinical outcomes in participants randomized to restrictive versus liberal red blood cell (RBC) transfusion thresholds (triggers) for all conditions. The restrictive transfusion threshold uses a lower haemoglobin level to trigger transfusion (most commonly 7 g/dL or 8 g/dL), and the liberal transfusion threshold uses a higher haemoglobin level to trigger transfusion (most commonly 9 g/dL to 10 g/dL). SEARCH METHODS We identified trials by searching CENTRAL (2016, Issue 4), MEDLINE (1946 to May 2016), Embase (1974 to May 2016), the Transfusion Evidence Library (1950 to May 2016), the Web of Science Conference Proceedings Citation Index (1990 to May 2016), and ongoing trial registries (27 May 2016). We also checked reference lists of other published reviews and relevant papers to identify any additional trials. SELECTION CRITERIA We included randomized trials where intervention groups were assigned on the basis of a clear transfusion 'trigger', described as a haemoglobin (Hb) or haematocrit (Hct) level below which a red blood cell (RBC) transfusion was to be administered. DATA COLLECTION AND ANALYSIS We pooled risk ratios of clinical outcomes across trials using a random-effects model. Two people extracted the data and assessed the risk of bias. We conducted predefined analyses by clinical subgroups. We defined participants randomly allocated to the lower transfusion threshold as 'restrictive transfusion' and to the higher transfusion threshold as 'liberal transfusion'. MAIN RESULTS A total of 31 trials, involving 12,587 participants, across a range of clinical specialities (e.g. surgery, critical care) met the eligibility criteria. The trial interventions were split fairly equally with regard to the haemoglobin concentration used to define the restrictive transfusion group. About half of them used a 7 g/dL threshold, and the other half used a restrictive transfusion threshold of 8 g/dL to 9 g/dL. The trials were generally at low risk of bias .Some items of methodological quality were unclear, including definitions and blinding for secondary outcomes.Restrictive transfusion strategies reduced the risk of receiving a RBC transfusion by 43% across a broad range of clinical specialties (risk ratio (RR) 0.57, 95% confidence interval (CI) 0.49 to 0.65; 12,587 participants, 31 trials; high-quality evidence), with a large amount of heterogeneity between trials (I(2) = 97%). Overall, restrictive transfusion strategies did not increase or decrease the risk of 30-day mortality compared with liberal transfusion strategies (RR 0.97, 95% CI 0.81 to 1.16, I(2) = 37%; N = 10,537; 23 trials; moderate-quality evidence) or any of the other outcomes assessed (i.e. cardiac events (low-quality evidence), myocardial infarction, stroke, thromboembolism (high-quality evidence)). Liberal transfusion did not affect the risk of infection (pneumonia, wound, or bacteraemia). AUTHORS' CONCLUSIONS Transfusing at a restrictive haemoglobin concentration of between 7 g/dL to 8 g/dL decreased the proportion of participants exposed to RBC transfusion by 43% across a broad range of clinical specialities. There was no evidence that a restrictive transfusion strategy impacts 30-day mortality or morbidity (i.e. mortality at other points, cardiac events, myocardial infarction, stroke, pneumonia, thromboembolism, infection) compared with a liberal transfusion strategy. There were insufficient data to inform the safety of transfusion policies in certain clinical subgroups, including acute coronary syndrome, myocardial infarction, neurological injury/traumatic brain injury, acute neurological disord
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Adverse effects of red blood cell transfusions in neonates: a systematic review and meta-analysis
Keir A, Pal S, Trivella M, Lieberman L, Callum J, Shehata N, Stanworth SJ
Transfusion. 2016;56((11):):2773-2780
Abstract
BACKGROUND Controversy exists regarding the contribution of blood transfusions to a range of adverse clinical outcomes in neonates. The aim of our systematic review was to identify the broader literature on harmful effects and associations potentially attributable to red blood cell (RBC) transfusions. STUDY DESIGN AND METHODS A comprehensive search of MEDLINE (PubMed) and EMBASE was undertaken. Eligible studies included both randomized controlled trials (RCTs) and nonrandomized studies examining the effects of small volume (10-20 mL/kg) RBC transfusions on neonates. Primary outcomes of interest were mortality, chronic lung disease, retinopathy of prematurity, necrotizing enterocolitis, and intraventricular hemorrhage. Two independent authors conducted a review of abstracts and then of full-text article reviews as well as data extraction and quality assessments. RESULTS Sixty-one studies were eligible for inclusion, including 16 (26%) randomized studies. The majority of studies were nonrandomized (n = 45; 74%), which included 32 observational studies with and 13 studies without a comparator group. There was no evidence that rates of mortality differed between restrictive and liberal strategies for transfusion (eight RCTs: risk ratio, 1.24; 95% confidence interval, 0.89-1.672, heterogeneity = 0%) or for necrotizing enterocolitis (five RCTs: risk ratio, 1.45; 95% confidence interval, 0.91-2.33; heterogeneity = 0%). A liberal strategy also was not superior to restrictive transfusion practice in the pooled randomized studies for rates of retinopathy of prematurity, chronic lung disease, or intraventricular hemorrhage. CONCLUSIONS Statistically significant differences in a range of harmful outcomes between neonates exposed to restrictive and liberal RBC transfusion practice were not found. However, the risks of bias identified in many studies and the lack of consistent reporting and definitions of events limits our conclusions.
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Length of red blood cell storage and clinical outcomes in transfused critical ill adults – the Age of Blood Evaluation (ABLE) randomised controlled trial
Lacroix L, Hebert PC, Fergusson DA, Tinmouth A, Cook DJ, Marshall, JC, Clayton L, McIntyre L, Callum J, et al
Transfusion Medicine. 2015;25((Suppl. 1)):6.. Abstract No. S10