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BackgroundThe 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 methodsWe 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 criteriaWe 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 resultsA 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' conclusionsTransfusion 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.

Introduction: Social prescribing offers a formal pathway of connecting patients in the health system with sources of support within the community to help improve their health and well‐being. Since its launch in March 2022, the Canadian Institute for Social Prescribing has acted as a collective impact network to identify, connect and build upon established social prescribing initiatives using a co‐design methodology. The institute received input from a participant advisory council, co‐design partners and several communities of interest groups. This study aimed to describe the perceptions of the Canadian Institute for Social Prescribing's role in advancing social prescribing using a co‐design approach and the barriers and facilitators to implementing social prescribing in Canada. Methods: We used a qualitative descriptive study design, document analysis, participant observation and semi‐structured individual interviews (n = 7) with members of the Canadian Institute for Social Prescribing co‐design group and the institute's leadership. We also analysed documents, field notes and transcripts using codebook thematic analysis. Results: Four themes were developed representing the facilitators of implementing the Canadian Institute for Social Prescribing to support social prescribing: Creating relational mechanisms (i.e., partnerships and connections), Bringing awareness to social prescribing and contributing to the evidence (i.e., values and beliefs), Addressing systemic conditions (i.e., having a common language for social prescribing and organizing the community health sector) and Enabling funding and policy to drive social prescribing initiatives (i.e., shifting evidence into policy and securing sustainable funding). Conclusion: Participants' reflections on the co‐design process demonstrated that the Canadian Institute for Social Prescribing development provided networking opportunities and shared resources relevant to social prescribing. Co‐design efforts also fostered relational and informational support, which laid the necessary groundwork in Canada to overcome the complex interplay between the macro‐ and micro‐level settings in which social prescribing is practiced. Patient or Public Contribution: The interviews and observations involved participants with lived experience of delivering, receiving or advocating for social prescribing. [ABSTRACT FROM AUTHOR]

Background Methods Results Conclusions Geriatric Emergency Department (ED) Guidelines recommend optimizing transitions of care for older patients with complex needs. In this study, we investigated referral patterns to interprofessional services, including occupational therapy, physiotherapy, dietician, social work, home care, and specialized geriatric services, among older adults presenting to the ED with high‐risk characteristics.We recruited community‐dwelling older adults presenting to 10 EDs across Ontario, Quebec, and Newfoundland, Canada, from April 2017 to July 2018. To observe processes of care in the ED, we deployed a two‐stage high‐risk case‐finding and focused comprehensive assessment process based on the interRAI ED‐Screener and ED Contact Assessment to identify and characterize older adults at high risk. We analyzed the secondary data using descriptive statistics and logistic regression.We screened 5265 individuals with the ED Screener, further assessed 1479 with the ED Contact Assessment, and analyzed data from a subset of 1055 community‐dwelling older adults assessed with the ED Contact Assessment. Participants in our study sample had a mean age of 83 years, 58% were female, and many had a complex burden of cognitive and functional impairment and social needs. Over half of this high‐needs sample were referred to general home care services (62.7%), occupational therapy (59.3%), and physiotherapy services (55.2%), while 16% were referred to specialized geriatric services. We also found a significant positive association between interprofessional referrals and the Assessment Urgency Algorithm and Institutional Risk Scale. The most important determinants of referral to interprofessional services were hospital province, functional, clinical, and social burden and support measures.The referral patterns identified suggest that patient needs and risk intensity did not always guide referral patterns in the Canadian EDs investigated. We suggest that EDs critically examine the appropriateness of their documentation and referral systems for supporting person‐centered care provision. [ABSTRACT FROM AUTHOR]

The authors reply to Chapalain and Aubron's fragility index analysis and Khan, Spertus, and Chan's Bayesian analysis, which both supplement the primary results of the Myocardial Ischemia and Transfusion trial. Their Bayesian analysis demonstrates a higher probability of harm from a restrictive transfusion strategy, endorsing the adoption of a liberal strategy in acute myocardial infarction and anemia patients, although acknowledging the tradeoff involved in increasing blood usage.

Background: The optimal hemoglobin threshold to guide red blood cell (RBC) transfusion for patients with acute myocardial infarction (MI) and anemia is uncertain., Objective: To estimate the efficacy of 4 individual hemoglobin thresholds (<10 g/dL [<100 g/L], <9 g/dL [<90 g/L], <8 g/dL [<80 g/L], and <7 g/dL [<70 g/L]) to guide transfusion in patients with acute MI and anemia., Design: Prespecified secondary analysis of the MINT (Myocardial Ischemia and Transfusion) trial using target trial emulation methods. (ClinicalTrials.gov: NCT02981407)., Setting: 144 clinical sites in 6 countries., Participants: 3492 MINT trial participants with acute MI and a hemoglobin level below 10 g/dL., Intervention: Four transfusion strategies to maintain patients' hemoglobin concentrations at or above thresholds of 10, 9, 8, or 7 g/dL. Protocol exceptions were permitted for specified adverse clinical events., Measurements: Data from the MINT trial were leveraged to emulate 4 transfusion strategies and estimate per protocol effects on the composite outcome of 30-day death or recurrent MI (death/MI) and 30-day death using inverse probability weighting., Results: The 30-day risk for death/MI was 14.8% (95% CI, 11.8% to 18.4%) for a <10-g/dL strategy, 15.1% (CI, 11.7% to 18.2%) for a <9-g/dL strategy, 15.9% (CI, 12.4% to 19.0%) for a <8-g/dL strategy, and 18.3% (CI, 14.6% to 22.0%) for a <7-g/dL strategy. Absolute risk differences and risk ratios relative to the <10-g/dL strategy for 30-day death/MI increased as thresholds decreased, although 95% CIs were wide. Findings were similar and imprecise for 30-day death., Limitation: Unmeasured confounding may have persisted despite adjustment., Conclusion: The 30-day risks for death/MI and death among patients with acute MI and anemia seem to increase progressively with lower hemoglobin concentration thresholds for transfusion. However, the imprecision around estimates from this target trial analysis precludes definitive conclusions about individual hemoglobin thresholds., Primary Funding Source: National Heart, Lung, and Blood Institute., Competing Interests: Disclosures: Disclosures can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M24-0571.

Background: The MINT trial raised concern for harm from a restrictive versus liberal transfusion strategy in patients with acute myocardial infarction (MI) and anemia. Type 1 and type 2 MI are distinct pathophysiological entities that may respond differently to blood transfusion. This analysis sought to determine if the effects of transfusion varied among patients with a type 1 or a type 2 MI and anemia. We hypothesized that the liberal transfusion strategy would be of greater benefit in type 2 than in type 1 MI., Methods: We compared rates of death or MI at 30 days in patients with type 1 (n=1460) and type 2 (n=1955) MI and anemia who were randomly allocated to a restrictive (threshold of 7 to 8 g/dL) or a liberal (threshold of 10 g/dL) transfusion strategy., Results: The primary outcome of death or MI was observed in 16% of type 1 MI and 15.4% of type 2 MI patients. The rate of death or MI was higher in patients with type 1 MI randomized to a restrictive (18.2%) versus liberal (13.2%) transfusion strategy (RR 1.32, 95% CI 1.04 - 1.67) with no difference observed between the restrictive (15.8% ) and liberal (15.1% ) transfusion strategies in patients with type 2 MI (RR 1.05 95% CI 0.85-1.29). The test for a differential effect of transfusion strategy by MI type was not statistically significant (P- interaction = 0.16)., Conclusions: The concern for harm with a restrictive transfusion strategy in patients with acute MI and anemia raised in the MINT primary outcome manuscript may be more apparent in patients with type 1 than type 2 MI., Clinical Trial Registration: ClinicalTrials.gov number, NCT02981407.

Background: The effect of a liberal transfusion strategy as compared with a restrictive strategy on outcomes in critically ill patients with traumatic brain injury is unclear., Methods: We randomly assigned adults with moderate or severe traumatic brain injury and anemia to receive transfusion of red cells according to a liberal strategy (transfusions initiated at a hemoglobin level of ≤10 g per deciliter) or a restrictive strategy (transfusions initiated at ≤7 g per deciliter). The primary outcome was an unfavorable outcome as assessed by the score on the Glasgow Outcome Scale-Extended at 6 months, which we categorized with the use of a sliding dichotomy that was based on the prognosis of each patient at baseline. Secondary outcomes included mortality, functional independence, quality of life, and depression at 6 months., Results: A total of 742 patients underwent randomization, with 371 assigned to each group. The analysis of the primary outcome included 722 patients. The median hemoglobin level in the intensive care unit was 10.8 g per deciliter in the group assigned to the liberal strategy and 8.8 g per deciliter in the group assigned to the restrictive strategy. An unfavorable outcome occurred in 249 of 364 patients (68.4%) in the liberal-strategy group and in 263 of 358 (73.5%) in the restrictive-strategy group (adjusted absolute difference, restrictive strategy vs. liberal strategy, 5.4 percentage points; 95% confidence interval, -2.9 to 13.7). Among survivors, a liberal strategy was associated with higher scores on some but not all the scales assessing functional independence and quality of life. No association was observed between the transfusion strategy and mortality or depression. Venous thromboembolic events occurred in 8.4% of the patients in each group, and acute respiratory distress syndrome occurred in 3.3% and 0.8% of patients in the liberal-strategy and restrictive-strategy groups, respectively., Conclusions: In critically ill patients with traumatic brain injury and anemia, a liberal transfusion strategy did not reduce the risk of an unfavorable neurologic outcome at 6 months. (Funded by the Canadian Institutes of Health Research and others; HEMOTION ClinicalTrials.gov number, NCT03260478.)., (Copyright © 2024 Massachusetts Medical Society.)

This is the protocol for an evidence and gap map. The objectives are as follows: This EGM aims to map available evidence on the effects of in-person interventions to reduce social isolation and/or loneliness across all age groups in all settings., (© 2023 The Authors. Campbell Systematic Reviews published by John Wiley & Sons Ltd on behalf of The Campbell Collaboration.)