Parenteral iron therapy in the anaemia of rheumatoid arthritis.

Thirty anaemic patients with active rheumatoid arthritis were each given 800 mg of iron , as iron dextran, intramuscularly over an interval of four weeks. The haemoglobin concentration rose significantly within two months in 26 of the patients but this was followed by a significant fall to the pre-treatment level nine months after treatment. The response to iron therapy was not related to the initial haemoglobin concentration, serum iron concentration, transferrin saturation nor to the amount of storage iron, whether assessed by bone marrow stainable iron or the serum ferritin concentration. There was an unexpected fall in the serum ferritin concentration within the first two months after treatment in half of the patients and this was followed by a rise towards the pre-treatment level during the following seven months, such that there was no apparent addition to the amount of storage iron over the period of the study. The possible mechanisms for these findings are discussed. A response to parenteral iron therapy in patients with active rheumatoid arthritis should not be regarded as evidence of iron deficiency and only by correction of the underlying inflammatory process will lasting improvement in the anaemia be obtained.