Epoetin responsiveness in peritoneal dialysis patients: a multi-center Slovenian study

The objective of our study was to assess the influence of residual renal function and other factors on epoetin requirements in chronic peritoneal dialysis patients. Fifty-one stable patients (mean age +/- SD: 52 +/- 13 years; 20 women) without recent bleeding, bone marrow disease or malignancy were recruited in four Slovenian centers. The target hemoglobin was above 110 g/L. The peritoneal equilibration test results and relevant clinical and laboratory parameters were recorded. The epoetin resistance index was expressed as a weekly epoetin dose/body weight/hemoglobin concentration. Twenty-four percent of the patients did not need epoetin treatment, the rest were treated with epoetin-beta in a dose of 70 +/- 56 U/kg per week s.c.; the hemoglobin concentration was 124 +/- 15 g/L. Ferritin >100 microg/L and transferrin saturation >20% fulfilled 63% of patients whose epoetin resistance index was not significantly lower (0.43 +/- 0.5 U/kg per week per g/L vs 0.6 +/- 0.72 U/kg per week per g/L, P = 0.502). No difference was found between diabetic and non-diabetic patients. Treatment with angiotensin system antagonists, but not with aluminum phosphate binders, was associated with increased epoetin resistance index (0.56 +/- 0.59 vs 0.3 +/- 0.4 U/kg per week per g/L, P = 0.038). No correlation between epoetin resistance index and residual glomerular filtration rate was found (r = -0.2, P = 0.173). A multiple linear regression analysis showed C-reactive protein, intact parathormone level, female sex and treatment with angiotensin system antagonists to be the independent predictors influencing epoetin resistance index. Our results show that systemic inflammation, secondary hyperparathyroidism and angiotensin system antagonist treatment are the most important modifiable parameters affecting epoetin requirements in stable peritoneal dialysis patients.