Anemia in the elderly.

As the population ages, increasing attention has become focused on the prevalence of anemia in elderly individuals. Anemia occurs in more than 10% of individuals who are older than the age of 65 years, and it increases to more than 50% in individuals who are older than the age of 80 years. Although the anemia is typically mild and unlikely to result in symptoms, it is uniformly associated with increased morbidity and mortality as assessed in large cohort studies. Anemia is an independent predictor of these adverse outcomes both in healthy community-dwelling subjects and in patients with significant co-morbidities. Efforts to understand the pathophysiology of anemia in this population, especially the one third of patients with "unexplained" anemia, have focused on the potential contributions of inflammatory pathways, erythropoietin resistance, and changes in hematopoietic stem cells to the age-dependent decrease in red cell mass. We would argue that these pathways are closely interrelated and combine to lead to anemia in aging individuals. This brief review summarizes the current understanding of this entity and our studies aimed at further delineating its pathophysiology.