Intravenous iron to treat anaemia following critical care: a multicentre feasibility randomised trial

Haemoglobin thresholds to define anaemia from age 6 months to 65 years: estimates from international data sources

BACKGROUND

Detection of anaemia is crucial for clinical medicine and public health. Current WHO anaemia definitions are based on statistical thresholds (fifth centiles) set more than 50 years ago. We sought to establish evidence for the statistical haemoglobin thresholds for anaemia that can be applied globally and inform WHO and clinical guidelines.

METHODS

In this analysis we identified international data sources from populations in the USA, England, Australia, China, the Netherlands, Canada, Ecuador, and Bangladesh with sufficient clinical and laboratory information collected between 1998 and 2020 to obtain a healthy reference sample. Individuals with clinical or biochemical evidence of a condition that could reduce haemoglobin concentrations were excluded. We estimated haemoglobin thresholds (ie, 5th centiles) for children aged 6-23 months, 24-59 months, 5-11 years, and 12-17 years, and adults aged 18-65 years (including during pregnancy) for individual datasets and pooled across data sources. We also collated findings from three large-scale genetic studies to summarise genetic variants affecting haemoglobin concentrations in different ancestral populations.

FINDINGS

We identified eight data sources comprising 18 individual datasets that were eligible for inclusion in the analysis. In pooled analyses, the haemoglobin fifth centile was 104·4 g/L (90% CI 103·5-105·3) in 924 children aged 6-23 months, 110·2 g/L (109·5-110·9) in 1874 children aged 24-59 months, and 114·4 g/L (113·6-115·2) in 1839 children aged 5-11 years. Values diverged by sex in adolescents and adults. In pooled analyses, the fifth centile was 122·2 g/L (90% CI 121·3-123·1) in 1741 female adolescents aged 12-17 years and 128·2 g/L (126·4-130·0) in 1103 male adolescents aged 12-17 years. In pooled analyses of adults aged 18-65 years, the fifth centile was 119·7 g/L (90% CI 119·1-120·3) in 3640 non-pregnant females and 134·9 g/L (134·2-135·6) in 2377 males. Fifth centiles in pregnancy were 110·3 g/L (90% CI 109·5-111·0) in the first trimester (n=772) and 105·9 g/L (104·0-107·7) in the second trimester (n=111), with insufficient data for analysis in the third trimester. There were insufficient data for adults older than 65 years. We did not identify ancestry-specific high prevalence of non-clinically relevant genetic variants that influence haemoglobin concentrations.

INTERPRETATION

Our results enable global harmonisation of clinical and public health haemoglobin thresholds for diagnosis of anaemia. Haemoglobin thresholds are similar between sexes until adolescence, after which males have higher thresholds than females. We did not find any evidence that thresholds should differ between people of differering ancestries.

FUNDING

World Health Organization and the Bill & Melinda Gates Foundation.

Pharmacotherapy for Reducing RBC Transfusion for Patients in the ICU: A Systematic Review and Network Meta-Analysis

OBJECTIVES

To determine optional therapeutic strategies by comparing monotherapies and combination therapies to reduce RBC transfusion requirement for patients in the ICU.

DATA SOURCES

MEDLINE, CENTRAL, and Embase were searched for studies published from database inception until July 2023.

DATA EXTRACTION

We included randomized controlled trials comparing erythropoiesis-stimulating agents (Epo), iron, combination therapy with iron and Epo, hypoxia-inducible factor prolyl hydroxylase inhibitor (HIF-PHI), vitamin D 3 (VD3), and placebo/no treatment. A frequentist network meta-analysis (NMA) was performed using a random effects model, and the confidence in NMA was rated.

DATA SYNTHESIS

Of 117 eligible studies, 75 studies (15,091 patients) were included in the quantitative analysis. Compared with placebo/no treatment, the combination therapy reduces the requirement for RBC transfusion (risk ratio [RR]: 0.60; 95% CI, 0.49-0.74; confidence rating: moderate). The Epo or iron monotherapy may reduce the requirement for RBC transfusion (RR: 0.81; 95% CI, 0.63-1.04; confidence rating: low; RR: 0.83; 95% CI, 0.70-0.98; confidence rating: low, respectively). Combination therapy may not increase the prevalence of both venous thromboembolism (VTE) (RR: 0.73; 95% CI, 0.25-2.08; confidence rating: low) and infection. Epo monotherapy may not increase the prevalence of VTE but may increase that of infections (RR: 1.27; 95% CI, 0.94-1.73; confidence rating: low). Iron monotherapy may not increase the prevalence of both VTE and infection. Evidence for VD3 and HIF-PHI remains uncertain.

CONCLUSIONS

Combination therapy with iron and Epo likely reduces the requirement for RBC transfusion and may be less harmful than other therapies.

Intravenous iron for critically ill children. Comparison of three dose regimens

BACKGROUND

Anemia is extremely common among patients admitted to pediatric intensive care. Alternative treatments to transfusions such as intravenous iron must be considered. There are no published data for a prospective intravenous (IV) iron study focused in the critically ill children. The objective is to examine the safety and efficacy of intravenous iron sucrose infusion to manage anemia in pediatric critical care. A secondary objective is to examine the effect of different dose regimens of iron sucrose (3, 5, and 7 mg/kg dose).

PROCEDURE

Prospective investigation of intravenous iron sucrose utilization at a tertiary pediatric intensive care unit between October 2017 and November 2022.

RESULTS

In all 115 patients received a total of 616 infusions of IV iron. Transferrin saturation index (TSI) was the most common altered iron deficiency biomarker (91.8%). After IV iron treatment, hemoglobin showed a significant increase within a 30-day follow-up (9.2 vs. 11.6 g/dL, p < .001). There was also a significant improvement in TSI and serum iron (p < .001). Iron deficit replacement was higher in the 7 mg/kg dose group (94%) compared to 85.9% in the 5 mg/kg regimen and 77.5% in the lower dose group (p = .008), requiring less doses and a shorter time. Very few mild adverse reactions were reported (1.3% of infusions), with no differences between groups. The most frequent adverse effect was gastrointestinal in three cases. There were no anaphylaxis-like or other serious/life-threatening adverse effects.

CONCLUSIONS

This is the first study to evaluate intravenous iron therapy in pediatric critical care, providing preliminary evidence of safety and efficacy of IV iron sucrose. The 7 mg/kg dose regimen showed higher iron deficit replacement in a shorter time, which could be beneficial in critically ill children.

Iron and erythropoietin to heal and recover after intensive care (ITHRIVE): A pilot randomised clinical trial

Objective

To determine the feasibility of a pivotal randomised clinical trial of intravenous (IV) iron and erythropoietin in adult survivors of critical illness with anaemia requiring treatment in the intensive care unit.

Design

An investigator-initiated, parallel group, placebo-controlled, randomised feasibility trial.

Setting

A tertiary intensive care unit (ICU) in Perth, Western Australia.

Participants

Adults with anaemia (haemoglobin <100 g/L), requiring ICU-level care for more than 48 h, and likely to be ready for ICU discharge within 24 h.

Interventions

A single dose of IV ferric carboxymaltose and Epoetin alfa (active group) or an equal volume of 0.9% saline (placebo group).

Main outcome measures

Study feasibility was considered met if the pilot achieved a recruitment rate of ≥2 participants per site per month, ≥90% of participants received their allocated study treatment, and≥ 90% of participants were followed up for the proposed pivotal trial primary outcome - days alive and at home to day 90 (DAH90).

Results

The 40-participant planned sample size included twenty in each group and was enrolled between 1/9/2021 and 2/3/2022. Participants spent a median of 3.4 days (interquartile range 2.8-5.1) in the ICU prior to enrolment and had a mean baseline haemoglobin of 83.7 g/L (standard deviation 6.7). The recruitment rate was 6.7 participants per month [95% confidence interval (CI) 4.8-9.0], DAH90 follow-up was 100% (95% CI 91.2%-100%), and 39 (97.5%, 95% CI 86.8%-99.9%) participants received the allocated study intervention. No serious adverse events were reported.

Conclusion

The iron and erythropoietin to heal and recover after intensive care (ITHRIVE) pilot demonstrated feasibility based on predefined participant recruitment, study drug administration, and follow-up thresholds.

Erythropoietin to treat anaemia in critical care patients: a multicentre feasibility study

Anaemia is common and associated with poor outcomes during and after critical illness. The use of erythropoietin to treat such anaemia is controversial with older studies showing mixed results. In this study, we aimed to evaluate the feasibility of performing a large multicentre randomised controlled trial of erythropoietin in this setting. We randomly allocated patients staying in the ICU for ≥ 72 h with haemoglobin ≤ 120 g.l-1 to either a weekly injection of erythropoietin (40,000 iu, maximum of five injections) or placebo (saline). The primary endpoint was feasibility (as measured by recruitment, randomisation and follow-up rates, and protocol compliance). Secondary endpoints included biological efficacy and clinical outcomes. Forty-two participants were recruited and randomly allocated, all participants received the allocated intervention, but one withdrew their consent and refused the use of their data, leaving 20 in the erythropoietin group and 21 in placebo group. Follow-up was completed for all patients who survived. The overall recruitment rate was 73.7% with 8.4 participants recruited on average per month. The last haemoglobin measured before hospital discharge (or death) was similar between the groups with a mean (SD) haemoglobin of 107 (21) vs. 95 (25) g.l-1 , mean difference (95%CI) 11 (-4-26), g.l-1 , p = 0.154. A large, multicentre randomised controlled trial of erythropoietin to treat anaemia in ICU patients is feasible and necessary to determine effects of erythropoietin on mortality in ICU anaemic patients.

Statistical haemoglobin thresholds to define anaemia across the lifecycle

Detection of anaemia is critical for clinical medicine and public health. Current WHO values that define anaemia are statistical thresholds (5 ^th centile) set over 50 years ago, and are presently <110g/L in children 6-59 months, <115g/L in children 5-11 years, <110g/L in pregnant women, <120g/L in children 12-14 years of age, <120g/L in non-pregnant women, and <130g/L in men. Haemoglobin is sensitive to iron and other nutrient deficiencies, medical illness and inflammation, and is impacted by genetic conditions; thus, careful exclusion of these conditions is crucial to obtain a healthy reference population. We identified data sources from which sufficient clinical and laboratory information was available to determine an apparently healthy reference sample. Individuals were excluded if they had any clinical or biochemical evidence of a condition that may diminish haemoglobin concentration. Discrete 5 ^th centiles were estimated along with two-sided 90% confidence intervals and estimates combined using a fixed-effect approach. Estimates for the 5 ^th centile of the healthy reference population in children were similar between sexes. Thresholds in children 6-23 months were 104.4g/L [90% CI 103.5, 105.3]; in children 24-59 months were 110.2g/L [109.5, 110.9]; and in children 5-11 years were 114.1g/L [113.2, 115.0]. Thresholds diverged by sex in adolescents and adults. In females and males 12-17 years, thresholds were 122.2g/L [121.3, 123.1] and 128.2 [126.4, 130.0], respectively. In adults 18-65 years, thresholds were 119.7g/L [119.1, 120.3] in non-pregnant females and 134.9g/L [134.2, 135.6] in males. Limited analyses indicated 5 ^th centiles in first-trimester pregnancy of 110.3g/L [109.5, 111.0] and 105.9g/L [104.0, 107.7] in the second trimester. All thresholds were robust to variations in definitions and analysis models. Using multiple datasets comprising Asian, African, and European ancestries, we did not identify novel high prevalence genetic variants that influence haemoglobin concentration, other than variants in genes known to cause important clinical disease, suggesting non-clinical genetic factors do not influence the 5 ^th centile between ancestries. Our results directly inform WHO guideline development and provide a platform for global harmonisation of laboratory, clinical and public health haemoglobin thresholds.

Association between anaemia and hospital readmissions in patients undergoing major surgery requiring postoperative intensive care

Anaemia is a common sequela of surgery, although its relationship with patient recovery is unclear. The goal of this investigation was to assess the associations between haemoglobin concentrations at the time of hospital discharge following major surgery and early post-hospitalisation outcomes, with a primary outcome of 30 day unanticipated hospital readmissions. This investigation includes data from two independent population-based observational cohorts of adult surgical patients (aged ≥ 18 years) requiring postoperative intensive care unit admission between 1 January 2010 and 31 December 2019 in hospitals in Olmsted County, Minnesota, and between 1 July 2010 and 30 June 2017 in the Kaiser Permanente Northern California integrated healthcare system, California. Cox proportional hazards models assessed the associations between discharge haemoglobin concentrations (per 10 g.l-1 ) and outcomes, with prespecified multivariable adjustment. A total of 3260 patients were included from Olmsted County hospitals and 29,452 from Kaiser Permanente Northern California. In adjusted analyses, each 10 g.l-1 decrease in haemoglobin at hospital discharge was associated with a 9% (hazard ratio 1.09, 95%CI 1.02-1.18; p = 0.014) and 8% increase (hazard ratio 1.08, 95%CI 1.06-1.11; p < 0.001) in the hazard for readmission within 30 days in Olmsted County and Kaiser Permanente Northern California, respectively. In a sensitivity analysis exploring relationships across varying levels of pre-operative anaemia severity, these associations remained consistent, with lower discharge haemoglobin concentrations associated with higher readmissions irrespective of pre-operative anaemia severity. Anaemia at hospital discharge in surgical patients requiring postoperative intensive care is associated with increased rates of hospital readmission in two large independent cohorts. Future studies are necessary to evaluate strategies to prevent and/or treat anaemia in these patients for the improvement of post-hospitalisation outcomes.

Practical Anemia Bundle for Sustained Blood Recovery (PABST-BR) in critical illness: a protocol for a randomised controlled trial

INTRODUCTION

Anaemia is highly prevalent in critical illness and is associated with impaired outcomes during and after hospitalisation. However, the impact of interventions designed to attenuate or treat anaemia during critical illness on post-hospitalisation haemoglobin recovery and functional outcomes is unclear.

METHODS AND ANALYSIS

The Practical Anemia Bundle for Sustained Blood Recovery (PABST-BR) clinical trial is a pragmatic, open-label, parallel group, single-centre, randomised clinical trial assessing the impact of a multifaceted anaemia prevention and treatment strategy versus standard care for improvement of haemoglobin concentrations and functional outcomes after critical illness. The intervention, which will be delivered early in critical illness for those with moderate-to-severe anaemia (ie, haemoglobin <100 g/L), includes three components: (1) optimised phlebotomy, (2) clinical decision support and (3) pharmacological anaemia treatment directed at the underlying aetiology of anaemia. In-person assessments will occur at 1 and 3 months post-hospitalisation for laboratory evaluations and multidimensional functional outcome assessments. The primary outcome is differences in haemoglobin concentrations between groups, with secondary endpoints of anaemia-related fatigue, physical function, cognition, mental health, quality of life, phlebotomy volumes and frequency, transfusions, readmissions and mortality through 1-year post-hospitalisation.

ETHICS AND DISSEMINATION

The study has been approved by the Institutional Review Board of the Mayo Clinic in Minnesota, USA. A Data Safety Monitoring Plan has been created in accordance with the policies of the Institutional Review Board and the study funder, the National Heart, Lung and Blood Institute of the National Institutes of Health (NIH). The study will comply with NIH data sharing and dissemination policies. Results will be presented at national and international meetings and published in peer-reviewed journals. Designing and testing strategies to optimise haemoglobin recovery and improve functional outcomes after critical illness remain important research gaps. The PABST-BR trial will inform the development of a larger multicentre clinical trial.

TRIAL REGISTRATION NUMBER

NCT05167734.

The management of peri-operative anaemia in patients undergoing major abdominal surgery in Australia and New Zealand: a prospective cohort study

OBJECTIVES

To assess the prevalence and management of anaemia in patients undergoing major abdominal surgery, and the influence of guideline adherence on patient outcomes.

DESIGN

Prospective observational cohort study.

SETTING

56 hospitals in Australia and New Zealand.

PARTICIPANTS

People aged 18 years or more who underwent major abdominal surgery during two 2-week periods in July 2021.

MAIN OUTCOME MEASURES

Proportions of patients managed according to Australian National Blood Authority patient blood management guidelines.

SECONDARY OUTCOMES

anaemia prevalence, post-operative complications, length of hospital stay, re-admission within 30 days of discharge.

RESULTS

Data were available for 2730 eligible patients (mean age, 56.7 years; SD, 17.3 years), including 1558 women (57.1%). Haemoglobin levels prior to surgery were documented for 2461 of 2727 patients (90.2%), 689 of whom had anaemia (28.0%). Pre-operative anaemia assessment and management were associated with lower likelihood of intra-operative (adjusted odds ratio [aOR], 0.33; 95% CI, 0.19-0.57) and post-operative blood transfusion (aOR, 0.36; 95% CI, 0.25-0.53), and of post-operative complications (aOR, 0.79; 95% CI, 0.63-0.99). Tranexamic acid was administered during 128 of 2728 procedures (4.7%); a restrictive transfusion strategy was followed for 96 of the 167 patients who received post-operative blood transfusions (58%). Post-operative anaemia was identified in 1227 of 2069 patients (59.3%) in whom haemoglobin was assessed prior to discharge. The proportion of people re-admitted to hospital within 30 days was larger for patients with anaemia at discharge (169 of 1207 patients followed up, 14.0% v 61 of 825, 7.4%). Haemoglobin assessments were recorded by 30 days after discharge for only 288 patients with post-operative anaemia (24.3%).

CONCLUSIONS

The management of peri-operative anaemia differs between hospitals in Australia and New Zealand, with consequences for patient outcomes. Patients are often discharged after surgery with anaemia, which is therefore a potential therapeutic target.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry, ACTRN12621001517864 (retrospective).

The Efficacy and Safety of Intravenous Iron in Geriatric Hip Fracture Surgeries: A Systematic Review and Meta-Analysis

BACKGROUND

With the increasing evidence provided by recent high-quality studies, the intravenous iron appears to be a reliable therapy for blood administration in geriatric patients with hip fractures. Here, this systematic review and meta-analysis were aimed to assess the effectiveness and safety of intravenous iron in geriatric patients sustaining hip fractures.

METHODS

Potential pertinent literatures evaluating the effects of intravenous iron in the geriatric patients undergoing hip fractures were identified from Web of Science, PubMed, Embase, and Scopus. We performed a pairwise meta-analysis using fixed- and random-effects models, and the pooling of data was carried out by using RevMan 5.1.

RESULTS

Four randomized controlled trials and four observational studies conform to inclusion criteria. The results of meta-analysis showed that intravenous iron reduced transfusion rates compared to the control group, yet the result did not reach statistical significance. The intravenous iron was related to lower transfusion volumes, shorter length of stay, and a reduced risk of nosocomial infections. And there was no significant difference in terms of the mortality and other complications between the treatment group and the control group.

CONCLUSION

Current evidence suggests that intravenous iron reduces the transfusion volume, length of hospital stay, and risk of nosocomial infections. It takes about 7 days for intravenous iron to elevate hemoglobin by 1 g/dl and about 1 month for 2 g/dl. The safety profile of intravenous iron is also reassuring, and additional high-quality studies are needed.

Evaluation of perturbed iron-homeostasis in a prospective cohort of patients with COVID-19

Background: Marked reductions in serum iron concentrations are commonly induced during the acute phase of infection. This phenomenon, termed hypoferremia of inflammation, leads to inflammatory anemia, but could also have broader pathophysiological implications. In patients with coronavirus disease 2019 (COVID-19), hypoferremia is associated with disease severity and poorer outcomes, although there are few reported cohorts. Methods: In this study, we leverage a well characterised prospective cohort of hospitalised COVID-19 patients and perform a set of analyses focussing on iron and related biomarkers and both acute severity of COVID-19 and longer-term symptomatology. Results: We observed no associations between acute serum iron and long-term outcomes (including fatigue, breathlessness or quality of life); however, lower haemoglobin was associated with poorer quality of life. We also quantified iron homeostasis associated parameters, demonstrating that among 50 circulating mediators of inflammation IL-6 concentrations were strongly associated with serum iron, consistent with its central role in inflammatory control of iron homeostasis. Surprisingly, we observed no association between serum hepcidin and serum iron concentrations. We also observed elevated erythroferrone concentrations in COVID-19 patients with anaemia of inflammation. Conclusions: These results enhance our understanding of the regulation and pathophysiological consequences of disturbed iron homeostasis during SARS-CoV-2 infection.