Both IV and oral iron therapy were effective in increasing haemoglobin (Hb), serum ferritin and transferrin saturation (TSAT) levels, but the IV iron (ferric carboxymaltose) therapy group with a higher ferritin target was shown to be superior to oral iron in delaying and/or reducing the requirement for other anaemia management as well as producing a faster haematological response with a greater proportion of patients achieving an Hb increase of ≥1 g/dL [3]. This evidence concerns the gene GSTM1 and anemia (phenotype).