PREDICTION OF IRON-DEFICIENCY IN CHRONIC INFLAMMATORY RHEUMATIC DISEASE ANEMIA

We prospectively studied 45 anaemic patients (37 women, 8 men: with ch ronic inflammatory rheumatic diseases, The combination of serum ferrit in and CRP (as well as ESR) in its predictive capacity for bone marrow iron stores was examined. The relationship between other iron-related measurements (transferrin, transferrin saturation, soluble transferri n receptor, erythrocyte porphyrins and percentage of hypochromic/micro cytic erythrocytes) and bone marrow iron stores was also investigated. Stainable bone marrow iron was taken as the most suitable standard to separate iron-deficient from iron-replete patients. 14 patients (31%) were lacking bone marrow iron. Regression analysis showed a good corr elation between ferritin and bone marrow iron (adjusted R(2)=0.721, P< 0.0001). The combination of ferritin and CRP (ESR) did not improve the predictive power for bone marrow iron (adjusted R(2)=0.715) in this c ohort of patients with low systemic inflammatory activity, With respec t to the bone marrow iron content the best predictive cut-off value of ferritin was 30 mu g/l (86% sensitivity, 90% specificity), The other iron-related parameters both individually and when combined were less powerful in predicting bone marrow iron than ferritin alone, Only zinc bound erythrocyte protoporphyrin in combination with ferritin slightl y improved prediction (adjusted R(2)=0.731). A cut-off point of 11% hy pochromic erythrocytes reached a high specificity (90%), but was less sensitive (77%).