Effect of iron supplementation on iron stores and total body iron after whole blood donation

Cable RG ; Brambilla D ; Glynn SA ; Kleinman S ; Mast AE ; Spencer BR ; Stone M & Kiss JE

American Red Cross, Farmington, Connecticut; RTI, Rockville, Maryland; National Heart, Lung, and Blood Institute, Bethesda, Maryland; University of British Columbia, Victoria, British Columbia, Canada; Blood Center of Wisconsin, Milwaukee, Wisconsin; American Red Cross, Dedham, Massachusetts; Blood Systems Research Institute, San Francisco, California; Institute for Transfusion Medicine, Pittsburgh, Pennsylvania, Transfusion. 2016 May 27. doi: 10.1111/trf.13659. [Epub ahead of print]

Over half of both female and male frequent blood donors have iron depletion. Iron supplements replete iron stores and improve hemoglobin to support blood donation. This randomized controlled clinical trial was conducted to assess the effect of daily iron supplements after blood donation on time to recovery of iron stores. Primary outcome: time to recovery of hemoglobin after donation measured at different interval up to 24 weeks.

Two hundred and fifteen adult blood donors were randomly assigned to one of two arms: Treatment (ferrous gluconate 37.5 mg elemental iron daily) or Control (no iron) for 24 weeks after blood donation with 193 donors completing the study. Participants were further stratified to gender, age, and iron status (iron depleted-low ferritin <26 ng/ml or iron repleted -higher ferritin >26 ng/mL).

All donors were tested for serum ferritin and hemoglobin at 3-7 days and 2, 4, 8, 12, 16 and 24 weeks. Soluble transferrin receptor was measured at 3-7days and 24 weeks. Total body iron was estimated by a ratio of soluble transferring receptor to ferritin.

Total body iron was significantly increased in donors receiving iron compared to no iron over eight weeks after donation, 367.8 mg (95% CI, 293.5-442.1) versus 224.1 mg (95% CI, 282.5 to 34.3) for donors with a baseline ferritin level of < 26 ng/mL and 167.8 mg (95% CI, 116.5-219.2) versus 268.1 mg (95% CI, 2136.7 to 0.5) for donors with a baseline ferritin level of > 26 ng/mL. A total of 88% of the benefit of iron supplementation occurred during the first 8 weeks after blood donation.

At 24 weeks, there was a 281.0 mg (95% CI, 223.4-338.6) increase in total body iron in the iron supplemented group compared to predonation whereas the donors in the control group had a decrease in total body iron by 74mg (95 % CI, -112.3 to -35.9; p < 0.0001) from predonation. Iron depleted donors who received oral iron had a more rapid recovery potentially due to absorption and increased erythropoietic response.

Conclusion: After blood donation, donors who received oral iron supplements compared to no supplementation replaced iron stores in eight weeks. Daily oral iron is advisable after blood donation to maintain body iron stores for future donation.