Systematic reviews and meta-analyses comparing mortality in restrictive and liberal haemoglobin thresholds for red cell transfusion: an overview of systematic reviews
BMC Med. 2020;18(1):154
BACKGROUND There are no overviews of systematic reviews investigating haemoglobin thresholds for transfusion. This is important as the literature on transfusion thresholds has grown considerably in recent years. Our aim was to synthesise evidence from systematic reviews and meta-analyses of the effects of restrictive and liberal transfusion strategies on mortality. METHODS This was a systematic review of systematic reviews (overview). We searched MEDLINE, Embase, Web of Science Core Collection, PubMed, Google Scholar, and the Joanna Briggs Institute EBP Database, from 2008 to 2018. We included systematic reviews and meta-analyses of randomised controlled trials comparing mortality in patients assigned to red cell transfusion strategies based on haemoglobin thresholds. Two independent reviewers extracted data and assessed methodological quality. We assessed the methodological quality of included reviews using AMSTAR 2 and the quality of evidence pooled using an algorithm to assign GRADE levels. RESULTS We included 19 systematic reviews reporting 33 meta-analyses of mortality outcomes from 53 unique randomised controlled trials. Of the 33 meta-analyses, one was graded as high quality, 15 were moderate, and 17 were low. Of the meta-analyses presenting high- to moderate-quality evidence, 12 (75.0%) reported no statistically significant difference in mortality between restrictive and liberal transfusion groups and four (25.0%) reported significantly lower mortality for patients assigned to a restrictive transfusion strategy. We found few systematic reviews addressed clinical differences between included studies: variation was observed in haemoglobin threshold concentrations, the absolute between group difference in haemoglobin threshold concentration, time to randomisation (resulting in transfusions administered prior to randomisation), and transfusion dosing regimens. CONCLUSIONS Meta-analyses graded as high to moderate quality indicate that in most patient populations no difference in mortality exists between patients assigned to a restrictive or liberal transfusion strategy. TRIAL REGISTRATION PROSPERO CRD42019120503.
Effect of ultra-short-term treatment of patients with iron deficiency or anaemia undergoing cardiac surgery: a prospective randomised trial
Patients assigned to red cell transfusion strategies based on haemoglobin thresholds (19 studies).
Restrictive transfusion strategy.
Liberal transfusion strategy.
Of the meta-analyses presenting high- to moderate-quality evidence, 12 reported no statistically significant difference in mortality between restrictive and liberal transfusion groups and 4 reported significantly lower mortality for patients assigned to a restrictive transfusion strategy. Few systematic reviews addressed clinical differences between included studies: variation was observed in haemoglobin threshold concentrations, the absolute between group difference in haemoglobin threshold concentration, time to randomisation, and transfusion dosing regimens.
Lancet (London, England). 2019
BACKGROUND Anaemia and iron deficiency are frequent in patients scheduled for cardiac surgery. This study assessed whether immediate preoperative treatment could result in reduced perioperative red blood cell (RBC) transfusions and improved outcome. METHODS In this single-centre, randomised, double-blind, parallel-group controlled study, patients undergoing elective cardiac surgery with anaemia (n=253; haemoglobin concentration (Hb) <120 g/L in women and Hb <130 g/L in men) or isolated iron deficiency (n=252; ferritin <100 mcg/L, no anaemia) were enrolled. Participants were randomly assigned (1:1) with the use of a computer-generated range minimisation (allocation probability 0.8) to receive either placebo or combination treatment consisting of a slow infusion of 20 mg/kg ferric carboxymaltose, 40 000 U subcutaneous erythropoietin alpha, 1 mg subcutaneous vitamin B12, and 5 mg oral folic acid or placebo on the day before surgery. Primary outcome was the number of RBC transfusions during the first 7 days. This trial is registered with ClinicalTrials.gov, number NCT02031289. FINDINGS Between Jan 9, 2014, and July 19, 2017, 1006 patients were enrolled; 505 with anaemia or isolated iron deficiency and 501 in the registry. The combination treatment significantly reduced RBC transfusions from a median of one unit in the placebo group (IQR 0-3) to zero units in the treatment group (0-2, during the first 7 days (odds ratio 0.70 [95% CI 0.50-0.98] for each threshold of number of RBC transfusions, p=0.036) and until postoperative day 90 (p=0.018). Despite fewer RBC units transfused, patients in the treatment group had a higher haemoglobin concentration, higher reticulocyte count, and a higher reticulocyte haemoglobin content during the first 7 days (p≤0.001). Combined allogeneic transfusions were less in the treatment group (0 [IQR 0-2]) versus the placebo group (1 [0-3]) during the first 7 days (p=0.038) and until postoperative day 90 (p=0.019). 73 (30%) serious adverse events were reported in the treatment group group versus 79 (33%) in the placebo group. INTERPRETATION An ultra-short-term combination treatment with intravenous iron, subcutaneous erythropoietin alpha, vitamin B12, and oral folic acid reduced RBC and total allogeneic blood product transfusions in patients with preoperative anaemia or isolated iron deficiency undergoing elective cardiac surgery. FUNDING Vifor Pharma and Swiss Foundation for Anaesthesia Research.
Intravenous iron or placebo for anaemia in intensive care: the IRONMAN multicentre randomized blinded trial : a randomized trial of IV iron in critical illness
Intensive Care Medicine. 2016;42((11):):1715-1722
PURPOSE Both anaemia and allogenic red blood cell transfusion are common and potentially harmful in patients admitted to the intensive care unit. Whilst intravenous iron may decrease anaemia and RBC transfusion requirement, the safety and efficacy of administering iron intravenously to critically ill patients is uncertain. METHODS The multicentre, randomized, placebo-controlled, blinded Intravenous Iron or Placebo for Anaemia in Intensive Care (IRONMAN) study was designed to test the hypothesis that, in anaemic critically ill patients admitted to the intensive care unit, early administration of intravenous iron, compared with placebo, reduces allogeneic red blood cell transfusion during hospital stay and increases the haemoglobin level at the time of hospital discharge. RESULTS Of 140 patients enrolled, 70 were assigned to intravenous iron and 70 to placebo. The iron group received 97 red blood cell units versus 136 red blood cell units in the placebo group, yielding an incidence rate ratio of 0.71 [95 % confidence interval (0.43-1.18), P = 0.19]. Overall, median haemoglobin at hospital discharge was significantly higher in the intravenous iron group than in the placebo group [107 (interquartile ratio IQR 97-115) vs. 100 g/L (IQR 89-111), P = 0.02]. There was no significant difference between the groups in any safety outcome. CONCLUSIONS In patients admitted to the intensive care unit who were anaemic, intravenous iron, compared with placebo, did not result in a significant lowering of red blood cell transfusion requirement during hospital stay. Patients who received intravenous iron had a significantly higher haemoglobin concentration at hospital discharge. The trial was registered at http://www.anzctr.org.au as # ACTRN12612001249842.
The IRONMAN trial: a protocol for a multicentre randomised placebo-controlled trial of intravenous iron in intensive care unit patients with anaemia
Critical Care & Resuscitation. 2014;16((4):):285-90.
BACKGROUND Allogeneic red blood cell (RBC) transfusion is associated with significant increases in mortality and major morbidity in patients admitted to the intensive care unit, and the blood supplies it requires are an increasingly scarce and costly resource. Despite high levels of compliance with recommended transfusion thresholds in the ICU, RBC transfusion remains common. Novel interventions to reduce the incidence of RBC transfusion are required. OBJECTIVE To describe the study protocol for a randomised controlled trial, the Intravenous Iron or Placebo for Anaemia in Intensive Care (IRONMAN) trial, comparing intravenous (IV) iron with placebo in patients who are admitted to an ICU and are anaemic. DESIGN, SETTING, PARTICIPANTS AND INTERVENTION A Phase IIb multicentre, randomised, placebo-controlled trial. Patients admitted to the ICU with a haemoglobin (Hb) level < 100 g/L and predicted to require critical care beyond the next calendar day will be randomly assigned in a 1 : 1 ratio to receive IV ferric carboxymaltose (500 mg) or placebo. MAIN OUTCOME MEASURES The primary end point will be the mean number of RBC units transfused from study enrolment to discharge from hospital. Secondary end points will include change in Hb level and incidence of nosocomial infection. RESULTS AND CONCLUSIONS The IRONMAN trial is designed to determine whether IV iron administered to patients admitted to an ICU and who are anaemic is associated with a reduction in RBC transfusion, compared with placebo in addition to standard care. The results of this trial may determine whether a Phase III trial of IV iron in ICUs is feasible. TRIAL REGISTRATION Australian New Zealand Clinical Trials Registry (ACTRN12612001249842). IS 1441-2772