Systematic reviews of guidelines and studies for single versus multiple unit transfusion strategies

Patterns of red blood cell utilization: Harnessing electronic health records data from the Information Standard for Blood and Transplant (ISBT) 128 system within the Biologics Effectiveness and Safety (BEST) initiative

BACKGROUND

Current hemovigilance methods generally rely on survey data or administrative claims data utilizing billing and revenue codes, each of which has limitations. We used electronic health records (EHR) linked to blood bank data to comprehensively characterize red blood cell (RBC) utilization patterns and trends in three healthcare systems participating in the U.S. Food and Drug Administration Center for Biologics Evaluation and Research Biologics Effectiveness and Safety (BEST) initiative.

METHODS

We used Information Standard for Blood and Transplant (ISBT) 128 codes linked to EHR from three healthcare systems data sources to identify and quantify RBC-transfused individuals, RBC transfusion episodes, transfused RBC units, and processing methods per year during 2012-2018.

RESULTS

There were 577,822 RBC units transfused among 112,705 patients comprising 345,373 transfusion episodes between 2012 and 2018. Utilization in terms of RBC units and patients increased slightly in one and decreased slightly in the other two healthcare facilities. About 90% of RBC-transfused patients had 1 (~46%) or 2-5 (~42%)transfusion episodes in 2018. Among the small proportion of patients with ≥12 transfusion episodes per year, approximately 60% of episodes included only one RBC unit. All facilities used leukocyte-reduced RBCs during the study period whereas irradiated RBC utilization patterns differed across facilities.

DISCUSSION

ISBT 128 codes and EHRs were used to observe patterns of RBC transfusion and modification methods at the unit level and patient level in three healthcare systems participating in the BEST initiative. This study shows that the ISBT 128 coding system in an EHR environment provides a feasible source for hemovigilance activities.

Rethinking the transfusion pathway in myelodysplastic syndromes: Study protocol for a novel randomized feasibility n-of-1 trial of weekly-interval red cell transfusion in myelodysplastic syndromes

BACKGROUND

Anemia in myelodysplastic syndromes (MDS) is associated with poorer health-related quality of life (HRQoL) and physical function, and is frequently treated with transfusions. The current common practice of transfusing multiple red blood cells (RBC) units every 2-4 weeks may result in peaks/troughs in hemoglobin (Hb) level, yet maintaining a stable Hb may better improve HRQoL. We describe a study protocol aiming to investigate the feasibility of weekly low-dose RBC transfusion in MDS patients, including assessing HRQoL and physical function outcomes.

STUDY DESIGN AND METHODS

In this n-of-1 pilot study, patients receive two treatment arms, with randomly allocated treatment sequence: arm A (patient's usual transfusion schedule) and arm B (weekly transfusion, individualized per patient). To facilitate timely delivery of weekly transfusion, extended-matched RBCs are provided, with transfusion based upon the previous week's Hb/pre-transfusion testing results to eliminate delays of awaiting contemporaneous cross-matching. Primary outcome is the feasibility of delivering weekly transfusion. Secondary outcomes include HRQoL, functional activity measurements, RBC usage, and alloimmunization rates. A qualitative substudy explores patient and staff experiences.

RESULTS

The trial is open in Australia, Netherlands, and UK. The first patient was recruited in 2020. Inter-country differences in providing RBCs are observed, including patient genotyping versus serological phenotyping to select compatible units.

DISCUSSION

This pilot trial evaluates a novel personalized transfusion approach of weekly matched RBC transfusion and challenges the dogma of current routine pre-transfusion matching practice. Findings on study feasibility, HRQoL, and physical functional outcomes and the qualitative substudy will inform the design of a larger definitive trial powered for clinical outcomes.

Effects of transfusing older red blood cells and platelets on obstetric patient outcomes: A retrospective cohort study

OBJECTIVE

To investigate associations between transfusion of blood products close to the end of shelf-life and clinical outcomes in obstetric inpatients.

METHODS

Mortality and morbidity were compared in patients transfused exclusively with red blood cells (RBC) stored for less than 21 days (fresh) versus RBC stored for 35 days or longer (old), and platelets (PLT) stored for 3 days or fewer (fresh) versus 4 days or longer (old) in Queensland, Australia from 2007 to 2013. Multivariable models were used to examine associations between these groups of blood products and clinical end points.

RESULTS

There were 3371 patients who received RBC and 280 patients who received PLT of the eligible storage durations. Patients transfused with old RBC received fewer transfusions (2.7 ± 1.8 vs. 2.3 ± 1.0 units; P < 0.001). However, a higher rate of single-unit transfusions was also seen in those patients who exclusively received old RBC (252 [9.3%] vs. 92 [13.7%]; P = 0.003). Comparison of fresh vs. old blood products revealed no differences in the quantities of transfused RBC (9.5 ± 5.9 vs. 9.1 ± 5.2 units; P = 0.680) or PLT (1.5 ± 0.8 vs. 1.4 ± 1.1 units; P = 0.301) as well as the length of hospital stay for RBC (3 [2-5] vs. 3 [2-5] days; P = 0.124) or PLT (5 [4-8] vs. 6 [4-9] days; P = 0.120).

CONCLUSION

Transfusing exclusively older RBC or PLT was not associated with increased morbidity or mortality.

[Peri- and Postoperative Anaemia Management]

Patient Blood Management (PBM) aims to diagnose and treat preoperative anaemia, avoid unnecessary blood loss, and enable rational use of blood products. Due to various limitations, treatment of preoperative anaemia has been successful in only a few German hospitals to date. Thus, the peri- and postoperative phase is increasingly becoming important for implementing various preventive and therapeutic measures for the treatment of (postoperative) anaemia. These will be comprehensively presented in the following.

Transfusion thresholds for guiding red blood cell transfusion

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.

Management and prevention of anemia (acute bleeding excluded) in adult critical care patients

OBJECTIVE

Anemia is very common in critical care patients, on admission (affecting about two thirds of patients), but also during and after their stay, due to repeated blood loss, the effects of inflammation on erythropoiesis, a decreased red blood cell life span, and haemodilution. Anemia is associated with severity of illness and length of stay.

METHODS

A committee composed of 16 experts from four scientific societies, SFAR, SRLF, SFTS and SFVTT, evaluated three fields: (1) anaemia prevention, (2) transfusion strategies and (3) non-transfusion treatment of anaemia. Population, Intervention, Comparison, and Outcome (PICO) questions were reviewed and updated as needed, and evidence profiles were generated. Analysis of the literature and formulation of recommendations were then conducted according to the GRADE® methodology.

RESULTS

The SFAR-SRLF guideline panel provided ten statements concerning the management of anemia in adult critical care patients. Acute haemorrhage and chronic anemia were excluded from the scope of these recommendations. After two rounds of discussion and various amendments, a strong consensus was reached for ten recommendations. Three of these recommendations had a high level of evidence (GRADE 1±) and four had a low level of evidence (GRADE 2±). No GRADE recommendation could be provided for two questions in the absence of strong consensus.

CONCLUSIONS

The experts reached a substantial consensus for several strong recommendations for optimal patient management. The experts recommended phlebotomy reduction strategies, restrictive red blood cell transfusion and a single-unit transfusion policy, the use of red blood cells regardless of storage time, treatment of anemic patients with erythropoietin, especially after trauma, in the absence of contraindications and avoidance of iron therapy (except in the context of erythropoietin therapy).

Management and prevention of anemia (acute bleeding excluded) in adult critical care patients

Objective

Anemia is very common in critical care patients, on admission (affecting about two-thirds of patients), but also during and after their stay, due to repeated blood loss, the effects of inflammation on erythropoiesis, a decreased red blood cell life span, and haemodilution. Anemia is associated with severity of illness and length of stay.

Methods

A committee composed of 16 experts from four scientific societies, SFAR, SRLF, SFTS and SFVTT, evaluated three fields: (1) anemia prevention, (2) transfusion strategies and (3) non-transfusion treatment of anemia. Population, Intervention, Comparison, and Outcome (PICO) questions were reviewed and updated as needed, and evidence profiles were generated. Analysis of the literature and formulation of recommendations were then conducted according to the GRADE^® methodology.

Results

The SFAR–SRLF guideline panel provided ten statements concerning the management of anemia in adult critical care patients. Acute haemorrhage and chronic anemia were excluded from the scope of these recommendations. After two rounds of discussion and various amendments, a strong consensus was reached for ten recommendations. Three of these recommendations had a high level of evidence (GRADE 1±) and four had a low level of evidence (GRADE 2±). No GRADE recommendation could be provided for two questions in the absence of strong consensus.

Conclusions

The experts reached a substantial consensus for several strong recommendations for optimal patient management. The experts recommended phlebotomy reduction strategies, restrictive red blood cell transfusion and a single-unit transfusion policy, the use of red blood cells regardless of storage time, treatment of anaemic patients with erythropoietin, especially after trauma, in the absence of contraindications and avoidance of iron therapy (except in the context of erythropoietin therapy).