Iron deficiency and anemia of chronic disease in elderly women: a discriminant-analysis approach for differentiation

To differentiate iron-deficiency anemia and anemia associated with chronic inflammatory diseases in elderly women, subsets of laboratory, dietary, and functional assessment variables were obtained by using discriminant analysis. Fifty-one subjects (70-79 y of age) were classified into one of four groups on the basis of the presence of iron deficiency and chronic inflammatory disease. Iron deficiency was defined on the basis of a significant response in hemoglobin concentration after iron supplementation. The discriminating subset of laboratory tests consisted of measures for serum ferritin, plasma transferrin receptors, and erythrocyte sedimentation rate. The discriminant function classified subjects into iron-deficient, anemia of chronic disease, or a category in which the two coexist, with an error rate of 18.6%. The addition of other variables (dietary iron and functional assessment information) did not appreciably improve the classification. The results of these three key laboratory tests may help to identify functional iron deficiency in the presence of chronic inflammation.