Sex-mismatched red blood cell transfusions and mortality: A systematic review and meta-analysis
Vox sanguinis. 2019
BACKGROUND AND OBJECTIVES Selection of a compatible red blood cell (RBC) unit does not include matching for donor sex. This systematic review and meta-analysis aims to summarize the evidence examining the impact of sex-mismatched RBC transfusion on recipient mortality. MATERIALS AND METHODS Ovid MEDLINE, Ovid EMBASE, CINAHL, PubMed, Web of Science and the Cochrane Database of Systematic Reviews were searched from inception up to 23 November 2018. Randomized controlled trials and observational studies were included in the search. Eligible studies reported on the impact of sex-matched compared to sex-mismatched RBC transfusion on recipient mortality. Two investigators independently extracted data and assessed study quality. A three-level meta-analytic model was applied to emphasize the unknown dependence among the effect sizes. RESULTS Five retrospective observational studies (n = 86 737) were included; no RCTs were found. Sex-mismatched RBC transfusions were associated with a higher risk of death compared with sex-matched transfusions (pooled hazard ratio [HR]: 1.13; 95% confidence interval [CI]: 1.02-1.24). In the subgroup of cardiovascular surgery (n = 57 712), there was no significant increase in mortality with sex-mismatched transfusions (pooled HR: 1.08; 95% CI: 0.95-1.22). The data were prone to confounding, selection bias and reporting bias. Certainty of the evidence was very low. CONCLUSION Sex-mismatched RBC transfusions were associated with an increased risk of death in this pooled analysis. However, the certainty of the evidence was very low from observational studies. The need to match donor and recipient sex for transfusions requires further investigation because of the potential widespread impact.
Systematic reviews of guidelines and studies for single versus multiple unit transfusion strategies
BACKGROUND Recent recommendations indicate that one red blood cell (RBC) unit should be transfused at a time, with reassessment after each transfusion, which may be extrapolated from literature supporting restrictive transfusion triggers rather than specific evidence. Therefore, two systematic reviews were performed to identify the following: 1) RBC transfusion guidelines and review articles to determine if single- or multiple-unit transfusion strategies are recommended and 2) studies comparing strategies for evidence of benefit. STUDY DESIGN AND METHODS MEDLINE, EMBASE, CINAHL, Web of Science, National Guideline Clearinghouse, and Trip Database were searched (inception to June 2017). For the first review, the proportion of articles with single/multiple-unit recommendations was assessed and stratified by article type. For the second review, the primary outcome was RBC use. Secondary outcomes included proportion of transfusion episodes using a single-unit strategy, length of stay, and mortality. RESULTS The first review identified 145 articles for analysis, with 51 transfusion guidelines. Only 14 guidelines (27%) made a recommendation, with most (93%) recommending single-unit transfusions. The second review identified seven cohort studies comparing preimplementation and postimplementation of a policy encouraging single-unit transfusion strategies. Meta-analysis could not be performed for outcomes given inconsistencies in reporting. RBC use decreased by approximately 10 to 41% across studies. CONCLUSION Transfusion guidelines lack recommendations to transfuse to a single-unit strategy. Mostly retrospective cohort studies (six of seven) are inconsistent in outcome reporting but suggest improved RBC use. Further high-quality studies could identify the benefits of a single-unit transfusion strategy, determine the applicability to different clinical settings, and inform future practice guidelines.
Mortality outcomes in patients transfused with fresher versus older red blood cells: a meta-analysis
Vox Sanguinis. 2017;112((3):):268-278
BACKGROUND Among transfused patients, the effect of the duration of red blood cell storage on mortality remains unclear. This study aims to compare the mortality of patients who were transfused with fresher versus older red blood cells. METHODS We performed an updated systematic search in the CENTRAL, MEDLINE, EMBASE and CINAHL databases, from January 2015 to October 2016. RCTs of hospitalized patients of any age comparing transfusion of fresher versus older red blood cells were eligible. We used a random-effects model to calculate pooled risk ratios (RRs) with corresponding 95% confidence interval (CI). RESULTS We identified 14 randomized trials that enrolled 26 374 participants. All-cause mortality occurred in 1219 of 9531 (12.8%) patients who received a transfusion of fresher red blood cells and 1810 of 16 843 (10.7%) in those who received older red blood cells (RR: 1.04, 95% CI: 0.98-1.12, P = 0.90, I2 = 0%, high certainty for ruling out benefit of fresh blood, moderate certainty for ruling out harm of fresh blood). In six studies, in-hospital death occurred in 691 of 7479 (9.2%) patients receiving fresher red cells and 1291 of 14 757 (8.8%) receiving older red cells (RR: 1.06, 95% CI: 0.97-1.15, P = 0.81, I2 = 0%, high certainty for ruling out benefit of fresh blood, moderate certainty for ruling out harm of fresh blood). CONCLUSION Transfusion of fresher red blood cells does not reduce overall or in-hospital mortality when compared with older red blood cells. Our results support the practice of transfusing patients with the oldest red blood cells available in the blood bank.
Systematic Reviews of Guidelines and Studies for Single Versus Multiple Unit Transfusion Strategies
Transfusion. 2017;57((53)):183A.. cp308.
Analysis of Red Blood Cell Storage Duration and in-Hospital Mortality Using Time Dependent Exposure: Is the Oldest Blood Bad?
Transfusion. 2017;57((53)):33A.. c26-a02c
Red blood cell storage and in-hospital mortality: a secondary analysis of the INFORM randomised controlled trial
The Lancet. Haematology. 2017;4((11):):e544-e552. e544
BACKGROUND No randomised trials have addressed whether exposure to red blood cells (RBCs) stored longer than 35 days is associated with harm in patients. We aimed to assess the risk of in-hospital mortality associated with transfusing blood stored longer than 35 days. METHODS We did a secondary analysis of the INforming Fresh versus Old Red cell Management (INFORM) trial, a pragmatic, multicentre, randomised controlled trial of patients (≥18 years) admitted to one of six hospitals in Australia, Canada, Israel, and the USA and expected to need RBC transfusions. Patients were randomly assigned (2:1) to receive blood in inventory stored for the longest time (standard care) or the shortest time, using a random allocation schedule and stratified by centre and patient ABO blood group. The primary objective of the INFORM trial was to assess all-cause in-hospital mortality in patients with blood group A and O who were transfused. For our exploratory secondary analysis, we classified individuals into one of three mutually exclusive exposure categories on the basis of the maximum storage duration of any blood unit patients had received on each day in hospital: exclusively exposed to RBCs stored no longer than 7 days, exposed to at least one unit of RBCs stored 8-35 days, and exposed to least one unit of RBCs stored longer than 35 days. Our primary objective was to determine the effect on risk of in-hospital death of time-dependent exposure to RBCs stored longer than 35 days compared with exclusive exposure to RBCs stored no longer than 7 days, both in patients of blood groups A and O and all patients. The INFORM trial is registered as an International Standard Randomised Controlled Trial, number ISRCTN08118744. FINDINGS Between April 2, 2012, and Oct 21, 2015, 31 497 patients were recruited, and 24 736 patients were eligible for inclusion in this analysis. We excluded nine patients for whom information about the storage duration of transfused blood was missing and one patient whose sex was unknown. 4480 (18%) patients were exposed to RBCs with longest storage, 1392 (6%) patients were exposed exclusively to RBCs with shortest storage, and 18 854 (76%) patients were exposed to RBCs stored 8-35 days. Median follow-up was 11 days (IQR 6-20). Exposure to RBCs stored longer than 35 days was not associated with increased risk of in-hospital death compared with exclusive exposure to the freshest RBC units after adjusting for demographic variables, diagnosis category, and blood product use history (in patients with blood group A or O: hazard ratio 0.94, 95% CI 0.73-1.20, p=0.60; in all patients: 0.91, 0.72-1.14, p=0.40). The risk of in-hospital death also did not differ between patients exposed to blood stored 8-35 days and patients exposed to blood stored 7 days or less (in patients with blood group A or O: 0.92, 0.74-1.15, p=0.48; in all patients: 0.90, 0.73-1.10, p=0.29). INTERPRETATION These data provide evidence that transfusion of blood stored for longer than 35 days has no effect on in-hospital mortality, which suggests that current approaches to blood storage and inventory management are reasonable. FUNDING Canadian Institutes for Health Research, Canadian Blood Services, and Health Canada.
Informing Fresh versus Old Red Cell Management (INFORM) trial: a large international pragmatic randomized trial
Transfusion. 2016;56((S4)):5A.. p6-030a.
Effect of short-term vs. long-term blood storage on mortality after transfusion
The New England Journal of Medicine. 2016;375((20):):1937-1945
Background Randomized, controlled trials have suggested that the transfusion of blood after prolonged storage does not increase the risk of adverse outcomes among patients, although most of these trials were restricted to high-risk populations and were not powered to detect small but clinically important differences in mortality. We sought to find out whether the duration of blood storage would have an effect on mortality after transfusion in a general population of hospitalized patients. Methods In this pragmatic, randomized, controlled trial conducted at six hospitals in four countries, we randomly assigned patients who required a red-cell transfusion to receive blood that had been stored for the shortest duration (short-term storage group) or the longest duration (long-term storage group) in a 1:2 ratio. Only patients with type A or O blood were included in the primary analysis, since pilot data suggested that our goal of achieving a difference in the mean duration of blood storage of at least 10 days would not be possible with other blood types. Written informed consent was waived because all the patients received treatment consistent with the current standard of care. The primary outcome was in-hospital mortality, which was estimated by means of a logistic-regression model after adjustment for study center and patient blood type. Results From April 2012 through October 2015, a total of 31,497 patients underwent randomization. Of these patients, 6761 who did not meet all the enrollment criteria were excluded after randomization. The primary analysis included 20,858 patients with type A or O blood. Of these patients, 6936 were assigned to the short-term storage group and 13,922 to the long-term storage group. The mean storage duration was 13.0 days in the short-term storage group and 23.6 days in the long-term storage group. There were 634 deaths (9.1%) in the short-term storage group and 1213 (8.7%) in the long-term storage group (odds ratio, 1.05; 95% confidence interval [CI], 0.95 to 1.16; P=0.34). When the analysis was expanded to include the 24,736 patients with any blood type, the results were similar, with rates of death of 9.1% and 8.8%, respectively (odds ratio, 1.04; 95% CI, 0.95 to 1.14; P=0.38). Additional results were consistent in three prespecified high-risk subgroups (patients undergoing cardiovascular surgery, those admitted to intensive care, and those with cancer). Conclusions Among patients in a general hospital population, there was no significant difference in the rate of death among those who underwent transfusion with the freshest available blood and those who underwent transfusion according to the standard practice of transfusing the oldest available blood. (Funded by the Canadian Institutes of Health Research and others; INFORM Current Controlled Trials number, ISRCTN08118744 .).
Transfusion of fresher vs older red blood cells in hospitalized patients: a systematic review and meta-analysis
The impact of transfusing fresher vs older red blood cells (RBCs) on patient-important outcomes remains controversial. Two recently published large trials have provided new evidence. We summarized results of randomized trials evaluating the impact of the age of transfused RBCs. We searched MEDLINE, EMBASE, CINAHL, the Cochrane Database for Systematic Reviews, and Cochrane CENTRAL for randomized controlled trials enrolling patients who were transfused fresher vs older RBCs and reported outcomes of death, adverse events, and infection. Independently and in duplicate, reviewers determined eligibility, risk of bias, and abstracted data. We conducted random effects meta-analyses and rated certainty (quality or confidence) of evidence using the GRADE approach. Of 12 trials that enrolled 5229 participants, 6 compared fresher RBCs with older RBCs and 6 compared fresher RBCs with current standard practice. There was little or no impact of fresher vs older RBCs on mortality (relative risk [RR], 1.04; 95% confidence interval [CI], 0.94-1.14; P = .45; I(2) = 0%, moderate certainty evidence) or on adverse events (RR, 1.02; 95% CI, 0.91-1.14; P = .74; I(2) = 0%, low certainty evidence). Fresher RBCs appeared to increase the risk of nosocomial infection (RR, 1.09; 95% CI, 1.00-1.18; P = .04; I(2) = 0%, risk difference 4.3%, low certainty evidence). Current evidence provides moderate certainty that use of fresher RBCs does not influence mortality, and low certainty that it does not influence adverse events but could possibly increase infection rates. The existing evidence provides no support for changing practices toward fresher RBC transfusion.
Clinical efficacy and safety of platelets in additive solution treated with two commercial pathogen reduction technologies
Transfusion. 2015;55((Suppl. 3)):3A.. Abstract no. P2-030A.