Erythropoietin in patients with anaemia in rheumatoid arthritis

Iron status and erythropoietin (Ep) level in serum and urine were determined in 30 patients with anaemia in rheumatoid arthritis. The anaemia in these patients was mild and fulfilled the criteria for anaemia of chronic disorders. The iron status of these patients differed from the iron status in patients with sideropenic anaemia. Serum Ep, level, measured indirectly by the polycythaemic mouse bioassay, was either not detected or when detected it did not correspond to the degree of anaemia. The data suggest that the failure to produce sufficient amount of Ep, among other causes, could be important in the pathogenesis of anaemia in rheumatoid arthritis.