Update on intravenous iron choices

Incidence of Iron Deficiency and the Role of Intravenous Iron Use in Perioperative Periods

Iron deficiency is a major problem in worldwide populations, being more alarming in surgical patients. In the presence of absolute iron deficiency (depletion of body iron), functional iron deficiency (during intense bone marrow stimulation by endogenous or exogenous factors), or iron sequestration (acute or chronic inflammatory conditions), iron-restricted erythropoiesis can develop. This systemic review was conducted to draw attention to the delicate problem of perioperative anemia, and to provide solutions to optimize the management of anemic surgical patients. Systemic reviews and meta-analyses, clinical studies and trials, case reports and international guidelines were studied, from a database of 50 articles. Bone marrow biopsy, serum ferritin levels, transferrin saturation, the mean corpuscular volume, and mean corpuscular hemoglobin concentration were used in the diagnosis of iron deficiency. There are various intravenous iron formulations, with different pharmacological profiles used for restoring iron. In surgical patients, anemia is an independent risk factor for morbidity and mortality. Therefore, anemia correction should be rapid, with parenteral iron formulations—the oral ones—being inefficient. Various studies showed the safety and efficacy of parenteral iron formulations in correcting hemoglobin levels and decreasing the blood transfusion rate, the overall mortality, the postoperative infections incidence, hospitalization days, and the general costs.

Ferric Gluconate Complex in Elderly Hospital Inpatients without Terminal Kidney Failure

BACKGROUND

Anemia is a common health issue for elderly patients. For patients with iron deficiency who cannot tolerate iron supplementation by the oral route, the parenteral route may be used. Options for parenteral iron supplementation include ferric gluconate complex (FGC).

OBJECTIVES

To evaluate the safety of FGC in elderly patients without terminal kidney failure and to assess its efficacy in treating iron-deficiency anemia.

METHODS

An observational chart review was conducted at a tertiary care university health centre. Patients included in the study were 65 years of age or older, had received at least 1 dose of FGC between January 1, 2014, and December 31, 2015, and had a hemoglobin count of less than 130 g/L (men) or less than 120 g/L (women) at baseline. For each patient, the observation period began when the first dose of FGC was administered and ended 60 days after the last dose. The main safety outcome (occurrence of any adverse reaction) was evaluated for every patient, with the efficacy analysis being limited to patients with a diagnosis of iron-deficiency anemia.

RESULTS

A total of 144 patients were included in the study, of whom 76 had iron-deficiency anemia. No serious, life-threatening adverse reactions were reported. The most commonly reported adverse reactions were nausea and vomiting. The mean increase in hemoglobin count was 13.5 g/L, a statistically significant change from baseline.

CONCLUSIONS

These results show that FGC is safe for use in elderly patients, with very few mild adverse reactions. Use of FGC led to increased hemoglobin count within 60 days. Of the 3 options for parenteral iron supplementation available in Canada, iron sucrose has not been studied in elderly patients, and iron dextran has a higher incidence of anaphylaxis, whereas FGC appears to be a safe alternative for patients with intolerance to oral iron.

Parenteral irons versus transfused red blood cells for treatment of anemia during canine experimental bacterial pneumonia

BACKGROUND

No studies have been performed comparing intravenous (IV) iron with transfused red blood cells (RBCs) for treating anemia during infection. In a previous report, transfused older RBCs increased free iron release and mortality in infected animals when compared to fresher cells. We hypothesized that treating anemia during infection with transfused fresh RBCs, with minimal free iron release, would prove superior to IV iron therapy.

STUDY DESIGN AND METHODS

Purpose-bred beagles (n = 42) with experimental Staphylococcus aureus pneumonia rendered anemic were randomized to be transfused RBCs stored for 7 days or one of two IV iron preparations (7 mg/kg), iron sucrose, a widely used preparation, or ferumoxytol, a newer formulation that blunts circulating iron levels.

RESULTS

Both irons increased the alveolar-arterial oxygen gradient at 24 to 48 hours (p = 0.02-0.001), worsened shock at 16 hours (p = 0.02-0.003, respectively), and reduced survival (transfusion 56%; iron sucrose 8%, p = 0.01; ferumoxytol 9%, p = 0.04). Compared to fresh RBC transfusion, plasma iron measured by non-transferrin-bound iron levels increased with iron sucrose at 7, 10, 13, 16, 24, and 48 hours (p = 0.04 to p < 0.0001) and ferumoxytol at 7, 24, and 48 hours (p = 0.04 to p = 0.004). No significant differences in cardiac filling pressures or performance, hemoglobin (Hb), or cell-free Hb were observed.

CONCLUSIONS

During canine experimental bacterial pneumonia, treatment of mild anemia with IV iron significantly increased free iron levels, shock, lung injury, and mortality compared to transfusion of fresh RBCs. This was true for iron preparations that do or do not blunt circulating free iron level elevations. These findings suggest that treatment of anemia with IV iron during infection should be undertaken with caution.

Core size determination and structural characterization of intravenous iron complexes by cryogenic transmission electron microscopy

Understanding physicochemical properties of intravenous (IV) iron drug products is essential to ensure the manufacturing process is consistent and streamlined. The history of physicochemical characterization of IV iron complex formulations stretches over several decades, with disparities in iron core size and particle morphology as the major source of debate. One of the main reasons for this controversy is room temperature sample preparation artifacts, which affect accurate determination of size, shape and agglomeration/aggregation of nanoscale iron particles. The present study is first to report the ultra-fine iron core structures of four IV iron complex formulations, sodium ferric gluconate, iron sucrose, low molecular weight iron dextran and ferumoxytol, using a cryogenic transmission electron microscopy (cryo-TEM) preservation technique, as opposed to the conventional room temperature (RT-TEM) technique. Our results show that room temperature preparation causes nanoparticle aggregation and deformation, while cryo-TEM preserves IV iron colloidal suspension in their native frozen-hydrated and undiluted state. In contrast to the current consensus in literature, all four IV iron colloids exhibit a similar morphology of their iron oxide cores with a spherical shape, narrow size distribution and an average size of 2nm. Moreover, out of the four tested formulations, ferumoxytol exhibits a cluster-like community of several iron carbohydrate particles which likely accounts for its large hydrodynamic size of 25nm, measured with dynamic light scattering. Our findings outline a suitable method for identifying colloidal nanoparticle core size in the native state, which is increasingly important for manufacturing and design control of complex drug formulations, such as IV iron drug products.