An inappropriate erythropoietic response to iron deficiency anaemia in the elderly

This study was carried out to clarify the features of iron deficiency anaemia in the elderly. Subjects were chosen from residents undergoing an annual health check in a home for the aged and the features of anaemia in the elderly were compared with those in middle-aged adults under 60 years old. The red cell count, red cell size and haemoglobin content in an elderly group with iron-deficiency anaemia did not differ from those in middle-aged adults. No significant differences of the serum ferritin and iron levels were noted between the two groups. Total iron binding capacity was higher in the middle-aged adults than in the elderly, while the reticulocyte count was significantly lower in the elderly group. Immature reticulocytes showing a considerable amount of residual RNA by flow cytometry with fluorescent staining were also lower in the elderly group than in the middle-aged adults. Serum erythropoietin levels in both groups were significantly higher than in non-anaemic age-matched controls and no difference in erythropoietin levels was noted between them. The ratio of the reticulocyte count to the log-transformed erythropoietin level was low in the elderly group with iron-deficiency anaemia compared with the middle-aged adults with iron deficiency anaemia. The same result was seen when the immature reticulocyte count was related to the log-transformed erythropoietin level. These findings suggest that the red cell production response to erythropoietin in the elderly with iron-deficiency anaemia might be inappropriate compared with both non-anaemic and anaemic middle-aged adults.