In 2003, the Transplant European Survey on Anemia Management (TRESAM) analyzed a cohort of 4,263 patients from 72 centers in 17 countries and found that only 18% of patients with Hb < 11 g/dL were receiving erythropoiesis stimulating agents (ESAs) [20]. This evidence concerns the gene GSTM1 and anemia (phenotype).