Atrial natriuretic peptide in aged patients with iron deficiency anemia

Abstract

Anemia is a common disease in elderly people. However, since hemoglobin concentration often decreases subclinically with aging because of nutritional impairment, its pathological significance is unclear. To investigate the pathological significance of low hemoglobin concentration, we studied the relation between hemoglobin levels and arrhythmia, as well as circulatory parameters. Arrhythmia was detected by Holter type ambulatory electrocardiography in 42 elderly people (aged 60 or over) living in a nursing home. Plasma concentrations of human atrial natriuretic peptide (hANP) after iron therapy were determined by immunoradiometric assay. Changes in circulatory parameters in elderly people with iron deficiency anemia were examined. Supraventricular and ventricular premature contractions significantly increased in elderly people with low hemoglobin concentrations or hematocrit. hANP increased significantly as the hemoglobin concentration decreased in 22 elderly people. Of these 22 subjects, 11 showed a low serum concentration of iron, and were administered ferrous salts. No side effects, such as nausea, occurred. After iron supplementation, the average hemoglobin level increased from 9.0 to 10.5 g/dl, and the average hANP level was reduced from 58.3±23.5 to 41.2±27.9 pg/ml, which was statistically significant by Wilcoxon's signed rank sum test. The increase in the hemoglobin level inversely correlated with the hANP level. Heart rate, blood pressure and body weight of subjects decreased significantly after iron supplementation therapy. Although hemoglobin levels were increased by iron supplementation therapy after a long period of anemia, the duration of the period with low hemoglobin levels showed no significant relation to initial hANP concentration. In conclusion, low hemoglobin levels induced secretion of hANP, and treatment of iron deficiency might exert favorable effects on the circulatory system.