Evidence for impaired erythropoietin response to anaemia in rheumatoid disease.

In this study we determined the serum erythropoietin (Epo) levels of 97 anaemic rheumatoid (RD) patients (Hb less than 11 g/dl) of whom 44 had serum ferritin greater than 60 micrograms/l (anaemia of chronic disorders; ACD), 26 had ferritin 20-60 micrograms/l and 27 had ferritin less than 20 micrograms/l. These results were compared with the Epo levels of 36 iron deficient controls (Hb less than 11 g/dl), 33 non-anaemic RD patients and 33 normals. The serum Epo levels of anaemic subjects were significantly higher (P less than 0.05) than those of non-anaemic patients. Despite similar Hb, the Epo results (geometric mean (confidence limits] of the ACD group (38 (32,45) mU/ml) and of RD patients with ferritin of 20-60 micrograms/l (39 (33,46)mU/ml) were significantly lower (P less than 0.05) than those of iron deficient controls (65 (52,80)mU/ml). When the Hb fell to 10 g/dl or less, the serum Epo of 13 RD patients with ferritin less than 20 micrograms/l was 65 (47,89)mU/ml, significantly lower (P less than 0.05) than that of 17 iron deficient controls (104 (78,136)mU/ml). These results justify clinical trials of recombinant human Epo in RD patients with ACD.