Evaluation of the Anemia of Rheumatoid Arthritis

Thirty-six patients with active rheumatoid arthritis in whom anemia was slight were investigated, in part with radioiron and radiochromium, for abnormalities which might lead to anemia.

The primary defect appeared to be a pronounced reduction of ability to absorb iron from the intestinal tract. There was an equally marked reduction in the serum concentration of iron which could not be attributed to the slight reduction in the iron-binding capacity of the serum. Despite the reduction level of iron in the serum, the apparent turnover of iron was so rapid that the total clearance per day was normal or moderately elevated. However, the fraction of the iron cleared from the blood and appearing in the circulation in newly synthesized erythrocytes was slighfly depressed. Erythrocyte survival was normal or very slightly shortened; hemolysis seems to play no important role. The fecal excretion of radioiron, not associated with erythrocytes, was greatly increased in two patients in whom there was no evidence of intestinal bleeding. A moderate increase in plasma vohime was common.