Change in red blood cell posttransfusion recovery between randomization arms and by prespecified subgroups. Bars represent mean change in red blood cell posttransfusion recovery between the second measure performed after randomization and the first measure before randomization to placebo (open blue circles) or iron repletion (open red triangles). (A) Overall change in posttransfusion recovery among all randomized participants completing the primary outcome measure and by (B) sex, (C) age, and (D) race. Error bars represent SD. ∗P < .05 by unpaired t test. ns, not significant.