The haematopoietic effect of recombinant human erythropoietin in haemodialysis is independent of the mode of administration (i.v. or s.c.)

Background: Previous studies comparing intravenous (i.v.) and subcutaneous (s.c.) administration of recombinant human erythropoietin (rHuEpo) often did not achieve optimal iron reserve, were restricted to a limited follow-up period (not allowing equilibration) and/or did not exclude the role of other confounding factors. In addition all papers focused on the conversion from i.v. to s.c. Methods: In this study, 30 equilibrated patients on s.c. rHuEpo were randomized into two groups, one converting to i.v. after 6 months of follow-up and one remaining on s.c. rHuEpo. In both groups rHuEpo was administered three times weekly. Only patients completing a further 6 months follow-up were considered for statistical evaluation. Serum ferritin was targeted at 200 ng/ml and haematocrits between 28 and 35% were pursued. Results: The average haematocrit levels before conversion were 31.9±1.1% in the conversion group and 31.4±1.6% at the same time point in the non-conversion group (P-NS). After 6 months haematocrits were 31.5±0.5% in the conversion group and 31.1±0.9% in the non-conversion group (P=NS). Ferritin concentration in the conversion group was 219±49 ng/ml before and 230±83 mg/ml after the conversion. For the non-conversion group ferritin was 224±25 ng/ml and 236±52 ng/ml respectively (P=NS). The weight-standardized average rHuEpo dose per injection remained the same in the conversion group before and after conversion (44.0±1.8 U/kg/injection vs 45.4±4.7 U/kg/injection) P=NS). In the non-conversion group the corresponding rHuEpo doses were 32.9±4.2 U/kg/injection and 39.6±7.0 U/kg/injection respectively (P=NS). There were no differences in serum PTH, aluminium, vitamin B12, folic-acid levels, and intake of co-trimoxazole, ACE inhibitors or theophylline. Conclusion: No changes in rHuEpo dose wee observed after conversion from s.c. to i.v. There were no significant differences between the conversion and non-conversion group. These results are in contrast to some earlier studies suggesting lower rHuEpo requirements in case of s.c. administration. Key words: anaemia; erythropoietin; intravenous erythropoietin; iron; subcutaneous erythropoietin