A randomized trial of blood donor iron repletion on red cell quality for transfusion and donor cognition and wellbeing.

Although altruistic regular blood donors are vital for the blood supply, many become iron deficient from donation-induced iron loss. The effects of blood donation-induced iron deficiency on red cell transfusion quality or donor cognition are unknown. In this double-blind, randomized trial, adult iron-deficient blood donors (n=79; ferritin <15 mg/L, and zinc protoporphyrin >60 mMol/mol heme) who met donation qualifications were enrolled. A first standard blood donation was followed by the gold-standard measure for red cell storage quality: a 51-chromium post-transfusion red cell recovery study. Donors were then randomized to intravenous iron repletion (one-gram low molecular weight iron dextran) or placebo. A second donation approximately five months later was followed by another recovery study. Primary outcome was the within-subject change in post-transfusion recovery. The primary outcome measure of an ancillary study reported here was the National Institutes of Health (NIH) Toolbox-derived uncorrected standard Cognition Fluid Composite Score. Overall, 983 donors were screened; 110 were iron-deficient and, of these, 39 were randomized to iron repletion and 40 to placebo. Red cell storage quality was unchanged by iron repletion: mean change in post-transfusion recovery was 1.6% (95% CI -0.5 - 3.8) and -0.4% (-2.0 - 1.2) with and without iron, respectively. Iron repletion did not affect any cognition or wellbeing measures. These data provide evidence that current criteria for blood donation preserve red cell transfusion quality for the recipient and protect adult donors from measurable effects of blood donation-induced iron deficiency on cognition. This trial was registered at www.clinicaltrials.gov as NCT02889133 and NCT02990559.