Is Anemia in Chronic Heart Failure Caused by Iron Deficiency?

Anemia in Patients With Advanced Heart FailureWe applaud Nanas et al. (1) on their attempt to elucidate the etiology of anemia in patients with advanced heart failure.We believe that clarification of some issues in their study regarding the definitions of anemia as well as potential introduction of surveillance bias would further improve its relevance.Defining anemia as "clinically significant" deviates from other standardized definitions-the World Health Organization (2) or Centers for Disease Control and Prevention criteria (3)-with implications for anemia prevalence.In addition, surveillance bias seems likely as only 2 of 37 patients were female derived from an unknown denominator.The ferritin concentration used by the investigators (Ͻ17 ng/ml, 38 pmol/l) is lower than other surveys (4) and expert reviews (5), hence, had a different threshold been applied, additional patients with iron deficiency anemia may have been discovered.Finally, the meaning of "the absence of iron stores" in the bone marrow is unclear without quantification or reporting of the stain used or inter-reader reliability.Additional data on the saturation index and correlation of serum markers with histological bone marrow findings would be most useful to other researchers in this area and potentially enhance the clinical applicability of the data.