Roles of Intravenous Iron Therapy in Various Patient Settings

Abstract

Iron deficiency is common and can occur in many patient populations. Many patients who have iron deficiency eventually develop anemia, which can contribute to a diminished quality of life, complications, increased hospitalization, and increased health-care costs. 1,2 Iron administration is often required and is an important adjunct to erythropoiesis-stimulating agent (ESA) therapy, which is often used to treat anemia. 3,4 The prevalence of anemia is approximately 45% in patients with stage 4 chronic kidney disease (CKD) and close to 100% in patients with stage 5 CKD. 4-6 Untreated anemia contributes to cardiovascular disease burden and risks of adverse outcomes, including angina, cardiac enlargement, ventricular hypertrophy, congestive heart failure, and death. 7,8 In the oncology setting, anemia is most often associated with the underlying malignancy and/or cancer treatment. 9-11 While up to 90% of cancer patients have anemia, less than 10% of this population was shown to be repleted with intravenous iron during ESA therapy, which in part may have contributed to the high rate (30-50%) of suboptimal responses to ESAs in patients with cancer. 12-16 In the intensive care unit (ICU) setting, approximately 70% of patients have anemia. Low hemoglobin levels in this setting have been associated with higher risks of hemodynamic instability, sepsis, and gastrointestinal bleeding, which translate to higher rates of mortality and various other complications. 17,18 Up to 61% of patients with heart failure have anemia, with more than 70% of the episodes attributed to iron deficiency anemia. 19,20 Anemia has a significant negative impact on the prognosis of heart failure, and studies have shown that the 1-year survival rate decreases from 74.4% to 55.6% when patients' hemoglobin levels decreased from >14.8 g/dL to <12.3 g/dL. 19 The etiologies of iron deficiency related to CKD, dialysis, oncology, critical illness, and heart failure are summarized in Table 1. 4,[21][22][23][24][25][26][27][28][29][30]