Randomized Study Comparing Ferric Carboxymaltose to Iron Sucrose to Treat Fe Deficiency in the Surgically Critically Ill

The inflammatory response associated with surgical critical illness rapidly induces a functional iron deficiency, characterized by hypoferremia, decreased transferrin saturation (TSAT), hyperferritinemia, and iron-deficient erythropoiesis (IDE). This functional iron deficiency both contributes to intensive care unit (ICU) anemia and increases the packed red blood cell (pRBCs) transfusion requirement. The goals of iron supplementation of critically ill surgical patients are to reverse the serum iron debt, eliminate IDE, improve anemia, and decrease pRBCs transfusions. Issues surrounding iron supplementation of this patient population include formulation, dose, route of administration, and mitigation of the complications of iron overload, including infection. The investigators first randomized clinical trial (RCT) of iron supplementation of critically ill surgical patients compared enteral ferrous sulfate 325 mg thrice daily to placebo (NCT00450177). Although a significant reduction in pRBCs transfusion requirement for the iron group was observed, low injury severity, intolerance of enteral medications, and a predominance of traumatic brain injury limited generalizability. In a second multicenter RCT, the investigators compared intravenous iron sucrose 100 mg thrice weekly to placebo among critically ill trauma patients (NCT01180894). Iron supplementation at this dose increased the TSAT only marginally (and not above the normal range) and increased the serum ferritin concentration significantly; however, there was no effect on IDE, anemia, or pRBCs transfusion requirement. In no instance did iron supplementation increase the risk of infection, despite a relatively high incidence of marked hyperferritinemia (serum ferritin concentration \> 1,000 ng/mL) in the iron group. The severity of both the serum and bone marrow iron debts observed in these trials led us to investigate alternative dosing schemes that deliver larger quantities of bioavailable iron safely. Ferric carboxymaltose (FCM) is a novel iron-containing complex that allows for the administration of a large replenishment dose of iron (up to 750 mg) over a short infusion period. Several pharmacodynamic properties of FCM render it appealing for use in the treatment of functional iron deficiency associated with surgical critical illness, including a short infusion time, a controlled, sustained delivery of iron to target tissues over a relatively long period of time (up to one week), and minimal hypersensitivity reactions. Increased efficacy and comparable safety have been reported for FCM as compared to iron sucrose for treatment of outpatients with iron-deficiency anemia. There are currently no data regarding the efficacy of FCM for the indication of functional iron deficiency associated with surgical critical illness. The aim of the current pilot trial is to compare two novel dosing schemes for treatment of functional iron deficiency in surgical ICU patients, both of which involve delivery of a larger total dose of iron as compared to both NCT00450177 and NCT01180894. The investigators hypothesize that iron supplementation with FCM, as compared to both iron sucrose and placebo, is more effective and equally safe for replacing the serum iron debt.