Prevention and management of acute reactions to intravenous iron in surgical patients

Iron Deficiency Related to Obesity

There is a direct correlation between being overweight and iron deficiency. Physiological changes occur in obese adipose cells that contribute to the development of iron deficiency (ID) and iron deficiency anemia (IDA). These changes disrupt the normal iron metabolic checks and balances. Furthermore, bariatric surgery can lead to long-term ID and IDA. Oral iron supplementation may not be effective for many of these patients. Intravenous iron infusions can significantly increase the quality of life for individuals experiencing this condition but are also associated with potentially serious complications. Adequate knowledge about intravenous (IV) iron administration can greatly increase the safety of this beneficial therapy. This review article explains the relationship between obesity, ID/IDA, bariatric surgery and the safe administration of IV iron.

Adverse events of iron and/or erythropoiesis-stimulating agent therapy in preoperatively anemic elective surgery patients: a systematic review

BACKGROUND

Iron supplementation and erythropoiesis-stimulating agent (ESA) administration represent the hallmark therapies in preoperative anemia treatment, as reflected in a set of evidence-based treatment recommendations made during the 2018 International Consensus Conference on Patient Blood Management. However, little is known about the safety of these therapies. This systematic review investigated the occurrence of adverse events (AEs) during or after treatment with iron and/or ESAs.

METHODS

Five databases (The Cochrane Library, MEDLINE, Embase, Transfusion Evidence Library, Web of Science) and two trial registries (ClinicalTrials.gov, WHO ICTRP) were searched until 23 May 2022. Randomized controlled trials (RCTs), cohort, and case-control studies investigating any AE during or after iron and/or ESA administration in adult elective surgery patients with preoperative anemia were eligible for inclusion and judged using the Cochrane Risk of Bias tools. The GRADE approach was used to assess the overall certainty of evidence.

RESULTS

Data from 26 RCTs and 16 cohort studies involving a total of 6062 patients were extracted, on 6 treatment comparisons: (1) intravenous (IV) versus oral iron, (2) IV iron versus usual care/no iron, (3) IV ferric carboxymaltose versus IV iron sucrose, (4) ESA+iron versus control (placebo and/or iron, no treatment), (5) ESA+IV iron versus ESA+oral iron, and (6) ESA+IV iron versus ESA+IV iron (different ESA dosing regimens). Most AE data concerned mortality/survival (n=24 studies), thromboembolic (n=22), infectious (n=20), cardiovascular (n=19) and gastrointestinal (n=14) AEs. Very low certainty evidence was assigned to all but one outcome category. This uncertainty results from both the low quantity and quality of AE data due to the high risk of bias caused by limitations in the study design, data collection, and reporting.

CONCLUSIONS

It remains unclear if ESA and/or iron therapy is associated with AEs in preoperatively anemic elective surgery patients. Future trial investigators should pay more attention to the systematic collection, measurement, documentation, and reporting of AE data.

Questions and answers on iron deficiency treatment selection and the use of intravenous iron in routine clinical practice

Iron deficiency is a common cause of morbidity and can arise as a consequence or complication from many diseases. The use of intravenous iron has increased significantly in the last decade, but concerns remain about indications and administration. Modern intravenous iron preparations can facilitate rapid iron repletion in one or two doses, both for absolute iron deficiency and, in the presence of inflammation, functional iron deficiency, where oral iron therapy is ineffective or has not worked. A multidisciplinary team of experts experienced in iron deficiency undertook a consensus review to support healthcare professionals with practical advice on managing iron deficiency in gastrointestinal, renal and cardiac disease, as well as; pregnancy, heavy menstrual bleeding, and surgery. We explain how intravenous iron may work where oral iron has not. We provide context on how and when intravenous iron should be administered, and informed opinion on potential benefits balanced with potential side-effects. We propose how intravenous iron side-effects can be anticipated in terms of what they may be and when they may occur. The aim of this consensus is to provide a practical basis for educating and preparing staff and patients on when and how iron infusions can be administered safely and efficiently. Key messages Iron deficiency treatment selection is driven by several factors, including the presence of inflammation, the time available for iron replenishment, and the anticipated risk of side-effects or intolerance. Intravenous iron preparations are indicated for the treatment of iron deficiency when oral preparations are ineffective or cannot be used, and therefore have applicability in a wide range of clinical contexts, including chronic inflammatory conditions, perioperative settings, and disorders associated with chronic blood loss. Adverse events occurring with intravenous iron can be anticipated according to when they typically occur, which provides a basis for educating and preparing staff and patients on how iron infusions can be administered safely and efficiently.

RAPIDIRON: Reducing Anaemia in Pregnancy in India-a 3-arm, randomized-controlled trial comparing the effectiveness of oral iron with single-dose intravenous iron in the treatment of iron deficiency anaemia in pregnant women and reducing low birth weight deliveries

Background

Anaemia is a worldwide problem and iron deficiency is the most common cause. In pregnancy, anaemia increases the risk of adverse maternal, foetal and neonatal outcomes.

India’s anaemia rate is among the highest in the world with India’s National Family Health Survey indicating over 50% of pregnant women were affected by anaemia.

India’s Anaemia Mukt Bharat-Intensified National Iron Plus Initiative aims to reduce the prevalence of anaemia among reproductive-age women, adolescents and children by 3% per year and facilitate the achievement of a Global World Health Assembly 2025 objective to achieve a 50% reduction of anaemia among women of reproductive age.

However, preliminary results of the NFHS-5 survey completed in 2020 indicate that anaemia rates are increasing in some states and these targets are unlikely to be achieved. With oral iron being the first-line treatment for iron deficiency anaemia (IDA) in pregnancy, these results are likely to be impacted by the side effects, poor adherence to tablet ingestion and low therapeutic impact of oral iron. These reports suggest a new approach to treating IDA, specifically the importance of single-dose intravenous iron infusions, may be the key to India effectively reaching its targets for anaemia reduction.

Methods

This 3-arm, randomized controlled trial is powered to report two primary outcomes. The first is to assess whether a single dose of two different intravenous formulations administered early in the second trimester of pregnancy to women with moderate IDA will result in a higher percentage of participants achieving a normal for pregnancy Hb concentration at 30–34 weeks’ gestation or just prior to delivery when compared to participants taking standard doses of oral iron. The second is a clinical outcome of low birth weight (LBW) (< 2500 g), with a hypothesis that the risk of LBW delivery will be lower in the intravenous iron arms when compared to the oral iron arm.

Discussion

The RAPIDIRON trial will provide evidence to determine if a single-dose intravenous iron infusion is more effective and economically feasible in reducing IDA in pregnancy than the current standard of care.

Trial registration

Clinical Trials Registry – India CTRI/2020/09/027730. Registered on 10 September 2020, http://ctri.nic.in/Clinicaltrials/showallp.php?mid1=46801&EncHid=&userName=anemia%20in%20pregnancy

Iron deficiency without anaemia: a diagnosis that matters

Iron deficiency anaemia (IDA) currently affects 1.2 billion people and iron deficiency without anaemia (IDWA) is at least twice as common. IDWA is poorly recognised by clinicians despite its high prevalence, probably because of suboptimal screening recommendations. Diagnosing IDWA relies on a combination of tests, including haemoglobin and ferritin levels, as well as transferrin saturation. Although the causes of iron deficiency may sometimes be obvious, many tend to be overlooked. Iron sufficiency throughout pregnancy is necessary for maternal and foetal health. Preoperative IDWA must be corrected to reduce the risk of transfusion and postoperative anaemia. Oral iron is the first-line treatment for managing IDWA; however, intravenous supplementation should be used in chronic inflammatory conditions and when oral therapy is poorly tolerated or ineffective. This review considers the causes and clinical features of IDWA, calls for greater awareness of the condition, and proposes diagnostic and management algorithms.

A multicenter study evaluating the effectiveness and safety of single-dose low molecular weight iron dextran vs single-dose ferumoxytol for the treatment of iron deficiency

There are multiple intravenous (IV) iron formulations available, of which several may be administered as single-dose infusions such as low-molecular weight iron dextran (LMWID), ferumoxytol, ferric carboxymaltose, and ferric derisomaltose. However, administration of ferumoxytol as a single-dose infusion is off-label as it is approved as a two-dose series. Previous studies of ferumoxytol alone support the effectiveness and safety of the single-dose regimen, but there is a paucity of data directly comparing single-dose ferumoxytol to other single-dose IV iron formulations. This multicenter cohort study sought to affirm the safety and effectiveness of single-dose ferumoxytol compared to single-dose LMWID. Overall, 906 patients who received single-dose LMWID (n = 439) or ferumoxytol (n = 467) were identified, of whom 351 met criteria for the primary effectiveness endpoint defined as median change in hemoglobin (Hb), hematocrit (Hct), and ferritin 8 to 12 weeks from baseline. All 906 patients were included for the secondary analysis evaluating the incidence of adverse events (AE) and requirement of additional IV iron infusions. Median change in Hb (LMWID 0.5 g/dL; ferumoxytol 0.8 g/dL; P = .24), Hct (LMWID 1.1%; ferumoxytol 1.25%; P = .89), and ferritin (LMWID 87 ng/dL; ferumoxytol 71 ng/dL; P = .47) was not significantly different between groups. Both groups experienced similar rates of AEs (LMWID 2.3%; ferumoxytol 2.8%; P = .63). The LMWID patients more frequently required additional IV iron infusions (LMWID 28.5%; ferumoxtyol 16.1%; P < .001). These findings support that single-dose ferumoxytol is effective and safe, and that patients may require fewer additional infusions compared to patients who received LMWID.

Management of Perioperative Iron Deficiency Anemia

Preoperative anemia affects 30-40% of patients undergoing major surgery and is an independent risk factor for perioperative blood transfusion, morbidity, and mortality. Absolute or functional iron deficiency is its leading cause. Nonanemic hematinic deficiencies are also prevalent and may hamper preoperative hemoglobin optimization and/or recovery from postoperative anemia. As modifiable risk factors, anemia and hematinic deficiencies should be detected and corrected prior to major surgical procedures. Postoperative anemia is even more common (up to 80-90%) due to surgery-associated blood loss, inflammation-induced blunted erythropoiesis, and/or preexisting anemia. Preoperative oral iron may have a role in mild-to-moderate anemia, provided there is sufficient time (6-8 weeks) and adequate tolerance of oral preparations. Postoperative oral iron is of little value and rife with gastrointestinal adverse events. Intravenous iron should preferentially be used in cases of moderate-to-severe iron deficiency anemia, concomitant use of erythropoiesis-stimulating agents, short time to surgery or nonelective procedures, and for postoperative anemia management. Minor infusion reactions to intravenous iron are rare, the incidence of severe anaphylactic reactions is extremely low, and there is no increase in infections with intravenous iron. Currently available intravenous iron formulations allowing administration of large single doses are preferred.

Patient blood management in obstetrics: prevention and treatment of postpartum haemorrhage. A NATA consensus statement

Patient blood management (PBM) is the timely application of evidence-informed medical and surgical concepts designed to maintain haemoglobin concentration, optimise haemostasis, and minimise blood loss in an effort to improve patient outcomes. The aim of this consensus statement is to provide recommendations on the prevention and treatment of postpartum haemorrhage as part of PBM in obstetrics. A multidisciplinary panel of physicians with expertise in obstetrics, anaesthesia, haematology, and transfusion medicine was convened by the Network for the Advancement of Patient Blood Management, Haemostasis and Thrombosis (NATA) in collaboration with the International Federation of Gynaecology and Obstetrics (FIGO), the European Board and College of Obstetrics and Gynaecology (EBCOG), and the European Society of Anaesthesiology (ESA). Members of the task force assessed the quantity, quality and consistency of the published evidence, and formulated recommendations using the system developed by the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) working group. The recommendations in this consensus statement are intended for use by clinical practitioners managing perinatal care of women in all settings, and by policy-makers in charge of decision making for the update of clinical practice in health care establishments.