There were no significant differences in haptoglobin, transferrin saturation, ferritin, incidence of iron deficiency and intact parathyroid hormone between the 2 groups, but presence of anaemia, reticulocyte, erythropoietin resistance index, ESA dose, frequency of iron supplementation and erythrocyte creatine levels were significantly higher in patients with increased haemoglobin concentrations compared to those without (Table 3). This evidence concerns the gene EPO and anemia (phenotype).