Importance: Although blood donation is allowed every 8 weeks in the United States, recovery of hemoglobin to the currently accepted standard (12.5 g/dL) is frequently delayed, and some donors become anemic.
Objective: To determine the effect of oral iron supplementation on hemoglobin recovery time (days to recovery of 80% of hemoglobin removed) and recovery of iron stores in iron-depleted ("low ferritin," ≤26 ng/mL) and iron-replete ("higher ferritin," >26 ng/mL) blood donors.
Design, setting, and participants: Randomized, nonblinded clinical trial of blood donors stratified by ferritin level, sex, and age conducted in 4 regional blood centers in the United States in 2012. Included were 215 eligible participants aged 18 to 79 years who had not donated whole blood or red blood cells within 4 months.
Interventions: One tablet of ferrous gluconate (37.5 mg of elemental iron) daily or no iron for 24 weeks (168 days) after donating a unit of whole blood (500 mL).
Main outcomes and measures: Time to recovery of 80% of the postdonation decrease in hemoglobin and recovery of ferritin level to baseline as a measure of iron stores.
Results: The mean baseline hemoglobin levels were comparable in the iron and no-iron groups and declined from a mean (SD) of 13.4 (1.1) g/dL to 12.0 (1.2) g/dL after donation in the low-ferritin group and from 14.2 (1.1) g/dL to 12.9 (1.2) g/dL in the higher-ferritin group. Compared with participants who did not receive iron supplementation, those who received iron supplementation had shortened time to 80% hemoglobin recovery in both the low-ferritin (mean, 32 days, interquartile range [IQR], 30-34, vs 158 days, IQR, 126->168) and higher-ferritin groups (31 days, IQR, 29-33, vs 78 days, IQR, 66-95). Median time to recovery to baseline ferritin levels in the low-ferritin group taking iron was 21 days (IQR, 12-84). For participants not taking iron, recovery to baseline was longer than 168 days (IQR, 128->168). Median time to recovery to baseline in the higher-ferritin group taking iron was 107 days (IQR, 75-141), and for participants not taking iron, recovery to baseline was longer than 168 days (IQR, >168->168). Recovery of iron stores in all participants who received supplements took a median of 76 days (IQR, 20-126); for participants not taking iron, median recovery time was longer than 168 days (IQR, 147->168 days; P < .001). Without iron supplements, 67% of participants did not recover iron stores by 168 days.
Conclusions and relevance: Among blood donors with normal hemoglobin levels, low-dose iron supplementation, compared with no supplementation, reduced time to 80% recovery of the postdonation decrease in hemoglobin concentration in donors with low ferritin (≤26 ng/mL) or higher ferritin (>26 ng/mL).
Trial registration: clinicaltrials.gov Identifier: NCT01555060.