Hemoglobin, serum albumin and plasma high-sensitivity C reactive protein levels (ELISA) will be recorded at baseline and every other month, together with nutritional and inflammation indices. Iron status will be evaluated on the basis of transferrin saturation and plasma ferritin levels. Reticulocytes and PTH levels will be also recorded. Equilibrated Kt/V will be calculated in order to estimate the dialysis dose of low molecular weight uraemic toxins, and the appearance of urea nitrogen will be calculated in order to estimate daily protein intake.