Adequacy of dialysis reduces the doses of recombinant erythropoietin independently from the use of biocompatible membranes in haemodialysis patients

Background. The effect of the adequacy of dialysis on the response to recom binant human erythropoietin (rHuEpo) therapy is still incompletely understo od because of many confounding factors such as iron deficiency, biocompatib ility of dialysis membranes, and dialysis modality that can interfere. Methods. We investigated the relationship between Kt/V and the weekly dose of rHuEpo in 68 stable haemodialysis (HD) patients (age 65+/-15 years) trea ted with bicarbonate HD and unsubstituted cellulose membranes for 6-343 mon ths (median 67 months). Inclusion criteria were HD for at least 6 months, s ubcutaneous rHuEpo for at least 4 months, transferrin saturation (TSAT) gre ater than or equal to 20%, serum ferritin greater than or equal to 100 ng/m l, and haematocrit (Hct) level targeted to 35% for at least 3 months. Exclu sion criteria included HBsAg and HIV positivity, need for blood transfusion s or evidence of blood loss in the 3 months before the study, and acute or chronic infections. Hct and haemoglobin (Hb) levels were evaluated weekly f or 4 weeks; TSAT, serum ferritin, Kt/V, PCRn, serum albumin (sAlb), and wee kly dose of rHuEpo were evaluated at the end of observation. No change in d ialysis or therapy prescription was made during the study. Results. The results for the whole group of patients were: Hct 35+/-1.2%, H b 12.1+/-0.6 g/dl, TSAT 29+/- 10%, serum ferritin 204+/-98 ng/ml, sAlb 4.1/-0.3 g/dl, Kt/V 1.33+/-0.19, PCRn 1.11+/-0.28 g/kg/day, weekly dose of rHu Epo 123+/-76 U/kg. Hct did not correlate with Kt/V, whereas rHuEpo dose and Kt/V were inversely correlated (r=-0.49; P<0.0001). Multiple regression an alysis with rHuEpo as dependent variable confirmed Kt/V as the only signifi cant variable (P<0.002). Division of the patients into two groups according to Kt/V (group A, Kt/V less than or equal to1.2; group B, Kt/V greater tha n or equal to1.4), showed no differences in Hct levels between the two grou ps, while weekly rHuEpo dose was significantly lower in group B than in gro up A (group B, 86+/-33 U/kg; group A, 183+/-95 U/kg, P<0.0001). Conclusions. In iron-replete HD patients treated with rHuEpo in the mainten ance phase, Kt/V exerts a significant sparing effect on rHuEpo requirement independent of the use of biocompatible synthetic membranes. By optimizing rHuEpo responsiveness, an adequate dialysis treatment can contribute to the reduction of the costs of rHuEpo therapy.