Iron deficiency (ID) was substituted with 1000 mg iron intravenous (i.v.)and 10000 international units (I.U.)of erythropoiesis-stimulating agent (ESA) subcutaneous (s.c.)or i.v., anemia of chronic disease (ACD) (without functional ID) with 40000 I.U. ESA s.c. or i.v and additionally 200 mg iron i.v.Substituted anemic patients in Group II (n = 32) showed a distinctly higher preoperative (Hb-median 13 versus 11.95 g/dL) (P < 0.01) and postoperative (Hb-median 9.75 versus 9.0 g/dL) (P < 0.05) Hb level compared with untreated anemic patients in Group I (n = 24). This evidence concerns the gene GSTM1 and nutritional disorder.