Anemia of aging: the role of chronic inflammation and cancer.
Aging is associated with increased incidence and prevalence of anemia, leading to a number of adverse health outcomes. These include death, functional dependence, increased risk of therapeutic complications, falls, and dementia. In approximately 30% of cases, anemia in older individuals is due to either relative or absolute erythropoietin (EPO) deficiency. Absolute EPO deficiency may be primary or secondary to declining renal function. Relative EPO deficiency is due to an age-related pro-inflammatory status that reduces the sensitivity of erythropoietic precursors to EPO. Despite this condition of EPO deficiency, the management of anemia of aging with erythropoiesis-stimulating agents (ESAs) is controversial, unless the anemia is due to renal insufficiency. The main concern related to this treatment arises from eight studies of ESAs in cancer, suggesting that ESAs may reduce patient survival in addition to increasing the risk of deep vein thrombosis. The results of these studies contrast with a host of other trials showing the safety of ESAs. The discrepancy may be explained in part by the fact that, in the trials suggesting a detrimental effect of ESAs, the goal was to obtain hemoglobin (Hb) levels higher than 12 g/dL. Because of this concern, correction of anemia in elderly individuals with relative EPO insufficiency should not be attempted outside clinical trials.