Serum erythropoietin levels in elderly inpatients with anemia of chronic disorders and iron deficiency anemia.

OBJECTIVE: To analyze the relationship between serum erythropoietin levels and hemoglobin levels in elderly patients with anemia of chronic disorders related to cancer or acute infection when compared with anemic patients with iron deficiency.

DESIGN: Prospective survey with comparison groups.

SETTING: Tertiary care center.

PATIENTS: An elderly group aged 70 and above (mean 84, range 70-96) was divided into subgroups of 45 with anemia of chronic disorders (23 with cancer and 22 with acute infection), 24 with iron-deficiency anemia, and 27 with no anemia. Thirty non-anemic younger adults were also studied.

MEASUREMENTS: Serum erythropoietin (radioimmunoassay), complete blood count, serum iron, B12, folate and ferritin, liver and kidney function tests, blood gas analyses, and bacteriological and radiological tests.

RESULTS: The serum erythropoietin levels were significantly lower in the elderly non-anemic hospitalized group than in the healthy younger group. A significant negative relationship between the log serum erythropoietin and hemoglobin levels was found in patients with iron deficiency, but not in the other groups. For any given hemoglobin level, the response of erythropoietin was significantly higher in anemic patients with iron deficiency when compared with the neoplastic and infectious group.

CONCLUSION: Erythropoietin response to anemia is blunted in elderly patients with anemia of chronic disorders related to cancer or acute infection. Erythropoietin level is lower in non-anemic elderly inpatients than in healthy younger persons.