Why Large Doses of IV Iron Decrease HD Patient Survival Is Unclear
This article is part of our ongoing coverage of Renal Week 2009. Click here for a complete list of our Renal Week Live articles.
- IV iron doses greater than 455 mg/month identify patients at high risk for death regardless of their transferrin saturation.
- These patients were much more likely to have received very high doses of epoetin alfa.
- The researchers ruled out underlying bleeding conditions that required administration of larger amounts of iron.
Very large doses of IV iron are associated with decreased long-term survival in patients on hemodialysis (HD), but a new analysis presented at ASN's Renal Week 2009 in San Diego probing this association could not establish a convincing reason for the increased mortality.
The researchers, Victor E. Pollak, MD, of the University of Colorado Health Science Center in Denver, and Jonathan A. Lorch, MD, of the Rogosin Institute, Weill-Cornell Medical College in New York, concluded that IV iron doses greater than 455 mg/month identify patients at high risk for death regardless of their transferrin saturation (TSAT) and also point out which patients require close follow-up.
Based on a study of 1,565 HD patients, the researchers concluded that it is unclear whether IV iron doses higher than 455 mg/month “are inherently toxic or rather identify patients who lose substantially greater amounts of iron, and whose mortality is increased as a result of continuing iron deficiency, the underlying cause of the iron loss, or both,” the authors wrote.
In a previous study published in BMC Nephrology (2009;10:6), Dr. Pollak and his colleagues found that, compared with HD patients receiving more than 455 mg/month of IV iron, those receiving 1-202 and 202-455 mg/month had a 73% and 51% decreased mortality risk, respectively.
The present analysis compared patients who received these large doses of iron with patients who received more modest amounts (50-455 mg/month). Patients who received more than 455 mg/month of IV iron were much more likely to have also received very high doses of epoetin alfa (EPO).
Despite very large doses of IV iron and EPO, patients who received more than 455 mg/month of IV iron had lower median hemoglobin, mean corpuscular hemoglobin, mean corpuscular volume, and TSAT.
Regarding the high death risk in the high iron group, the researchers ruled out obvious underlying bleeding conditions that required administration of larger amounts of iron.
Their study suggests that large doses of IV iron were given in response to persistently low TSAT levels in many patients, but the response of the TSAT level often was suboptimal, presumably leading physicians to persist in giving very large amounts of IV iron and EPO, the authors stated. They said their observations indicate that these patients are older and sicker and have a wide variety of clinical conditions, including severe underlying disease for some.