The haematopoietic effect of recombinant human erythropoietin in haemodialysis is independent of the mode of administration (iv or sc)

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 36% 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 +/- 8.3 ng/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 B-12, folic-acid levels, and intake of co-trimoxazole, ACE inhibitors or theophylline. Conclusion. No changes in rHuEpo dose were 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.