Change in haemoglobin concentration, haematocrit and vasoactive hormones in haemodialysis patients with erythropoietin-associated hypertension.

The changes in haemoglobin concentration, haematocrit, plasma renin activity (PRA) and atrial natriuretic peptide (ANP) were studied in 10 haemodialysis patients with erythropoietin-associated hypertension. All patients received intravenously 1500 IU of recombinant human erythropoietin (rHuEPO) thrice weekly for 24 weeks. Treatment with rHuEPO induced significant rises in haemoglobin concentration (p < 0.001) and haematocrit (p < 0.01). However, the difference between post- and pretreatment levels of haemoglobin (delta Hb) was not correlated with that between post- and pre-treatment mean blood pressure (delta MBP). No correlation was found between delta Ht (difference between post- and pre-treatment values of haematocrit) and delta MBP. These results indicate that elevation of the haematocrit and haemoglobin concentration of haemodialysis patients does not necessarily lead to an increase in blood pressure. In these patients, no significant differences were observed in PRA and ANP, comparing pre-treatment values with those measured 4, 8, 12 or 24 weeks after commencing rHuEPO. This suggests that neither PRA nor ANP play a central role in the pathogenesis of rHuEPO-induced hypertension.