. 2022 Sep 15;9:903739. doi: 10.3389/fmed.2022.903739

TABLE 4.

Indications for the use of intravenous iron in patients with gastrointestinal bleeding.

While in hospital	After hospital discharge
Where there is a need for rapid correction of moderate/severe iron deficiency anemia • Where there is iron deficiency and concomitant inflammatory status (CRP > 5 mg/dL) causing reduced absorption of oral iron due to the effects of hepcidin on ferroportin • In patients with gastrointestinal bleeding who also meet any of the following criteria: ° Need for imminent surgery (<30 days) with estimated perioperative blood loss > 1–1.5 L^* ° Need for invasive surgery with a risk of significant bleeding ° Need for erythropoiesis-stimulating agent treatment (preemptive intravenous iron is given to prevent non-response to EPO – the primary cause of which is functional iron deficiency^†) • Need for artificial feeding (parenteral or enteral) • As an alternative to blood transfusion (e.g., in patients who reject blood transfusion based on religious grounds or personal beliefs)	Where there is a need for rapid correction of moderate/severe iron deficiency anemia • When iron deposits are very low and there is a need for rapid repletion to initiate erythropoiesis • In the event of oral iron therapy failure due to: ° Intolerance of side effects that do not respond to recommended measures for improving tolerability ° Poor adherence ° Monthly increments of < 1 g/dL of hemoglobin (iron deficiency anemia that does not respond to oral iron)^‡,§ • Where there is a contraindication to oral iron preparations or another reason why oral iron cannot be used

While in hospital

After hospital discharge

Where there is a need for rapid correction of moderate/severe iron deficiency anemia
• Where there is iron deficiency and concomitant inflammatory status (CRP > 5 mg/dL) causing reduced absorption of oral iron due to the effects of hepcidin on ferroportin
• In patients with gastrointestinal bleeding who also meet any of the following criteria:
° Need for imminent surgery (<30 days) with estimated perioperative blood loss > 1–1.5 L^*
° Need for invasive surgery with a risk of significant bleeding
° Need for erythropoiesis-stimulating agent treatment (preemptive intravenous iron is given to prevent non-response to EPO – the primary cause of which is functional iron deficiency^†)
• Need for artificial feeding (parenteral or enteral)
• As an alternative to blood transfusion (e.g., in patients who reject blood transfusion based on religious grounds or personal beliefs)

Where there is a need for rapid correction of moderate/severe iron deficiency anemia
• When iron deposits are very low and there is a need for rapid repletion to initiate erythropoiesis
• In the event of oral iron therapy failure due to:
° Intolerance of side effects that do not respond to recommended measures for improving tolerability
° Poor adherence
° Monthly increments of < 1 g/dL of hemoglobin (iron deficiency anemia that does not respond to oral iron)^‡,§
• Where there is a contraindication to oral iron preparations or another reason why oral iron cannot be used

CRP, C-reactive protein; EPO, erythropoietin.

*For example, when bleeding is due to a resectable malignancy or the patient is admitted while awaiting orthopedic hip surgery.

^†A situation in which iron requirements exceed available iron stores. This term implies iron status with ferritin < 100 μg/dL and a transferrin saturation < 20% (or ferritin < 500 μg/L and a transferrin saturation < 30% in the presence of chronic kidney failure).

^‡Intravenous iron replacement therapy should be considered prior to discharge when factors that limit absorption have been identified during hospitalization.

^§Reasons that may explain refractoriness to oral iron include: interference with absorption (hypoacidity secondary to chronic autoimmune atrophic gastritis or the use of proton pump inhibitors, lymphocytic duodenosis due to Helicobacter pylori infection); reduced surface area available for absorption (gastrectomy, bariatric surgery); gluten-sensitive enteropathy or other clinical conditions that cause malabsorption, including edematous bowel loops due to heart or chronic kidney disease or severe hypoalbuminemia; or active inflammatory bowel disease. Other inflammatory conditions, such as systolic heart failure and left ventricular ejection fraction < 45%, should also be considered.