PURPOSE OF REVIEW:
There have been several large-scale epidemiologic studies, including the National Health and Nutrition Examination Survey III (NHANES III), which have described the prevalence and impact of anemia in the elderly. The information derived has been critically important. However, given the large number of patients surveyed, these reports necessarily relied substantially on the laboratory-based screening evaluations. There are now two recent reports describing the cause of anemia in elderly outpatients, and although the numbers are smaller than the large scale surveys, they constitute comprehensive hematologic evaluations with therapeutic interventions and clinical follow-up. The purpose of this review is to compare these different analyses.
There are distinct differences and similarities in the two types of studies, which are derived from patients seen in hematology clinics. Despite comprehensive hematologic evaluation, the puzzling entity of unexplained anemia of the elderly is confirmed and found to account for 30-46% of patients. NHANES III classified iron-deficiency anemia with other nutritional anemias, a classification that might be correct in the developing third world, but in North America and Western Europe, iron deficiency is more often caused by blood loss and the cause must be sought and dealt with. The myelodysplastic syndromes are an important cause of anemia in the elderly, with a prevalence of at least 4%.
Large-scale screening studies of anemia in the elderly are of great importance, and when complemented by comprehensive hematologic evaluations, provide a more accurate picture of the clinical situation.
Department of Medicine, Stanford University, Stanford, California 94305, USA.