Mean (SE) units packed red blood cells transfused by pre-treatment transfusion strata during the TRIUMPH and SHEPHERD studies.<br>P values for data from the TRIUMPH study (A) were calculated using Wilcoxon’s rank sum test. P values for data from the SHEPHERD study (B) were calculated using a sign rank test. Adapted from Schubert et al. Br J Haematol. 2008.¹²