2 Renal Anemia Treatment In Peritoneal Dialysis Patients: A Multicenter Slovenian Study

Abstract

Objectives The aim of our study was to: (i) assess the number of patients who need epoetin treatment and the adequacy of iron treatment, (ii) assess the influence of presence of diabetes mellitus, polycystic kidney disease and the influence of therapy with aluminum phosphate binders and angiotensin system antagonists on the epoetin requirements, (iii) assess the role of other factors possibly influencing epoetin resistance – secondary hyperparathyroidism, inflammation, dialysis dose and residual renal function.Design and Methods Fifty‐one stable peritoneal dialysis (PD) patients (mean age ± SD was 52 ± 13 years, 20 women) without recent bleeding, surgery, bone marrow disease, malignancy, or hypothyroidism were recruited in four Slovenian centers. The dose of epoetin was adjusted to maintain a target hemoglobin of above 110 g/L. At the time of inclusion (median 36 months of PD, range 3–124 months) the PET test results and relevant clinical and laboratory parameters were recorded. Index of epoetin resistance (IRE) was expressed as weekly epoetin dose/body weight/hemoglobin concentration.Results Twenty four percent of patients did not need epoetin treatment, the rest were treated with Epoetin‐beta at a dose of 70 ± 56 U/kg/week s.c.; hemoglobin concentration was 124 ± 15 g/L; 14% had hemoglobin below 110 g/L. Iron adequacy parameters (ferritin > 100 µg/L and TSAT > 20%) were fulfilled by 63% of patients, and their IRE was lower (0.43 ± 0.5 U/kg/week/g/L vs. 0.6 ± 0.72 U/kg/week/g/L), but not significantly (P = 0.502). Patients with polycystic kidneys had lower IRE (0.13 ± 0.3 vs. 0.52 ± 0.55 U/kg/week/g/L, P = 0.011) and majority of them (71%) did not need epoetin treatment (P = 0.006). No difference was found for diabetic patients. Treatment with angiotensin system antagonists, but not with aluminum phosphate binders, is associated with increased IRE (0.56 ± 0.59 vs. 0.3 ± 0.4 U/kg/week/g/L, P = 0.038). A statistically significant correlation was found for IRE and CRP (r = 0.48, P = 0.001) and iPTH (r = 0.46, P = 0.001). No correlation between IRE and residual renal function was found (r = −0.2, P = 0.173). Stepwise linear regression analysis for multiple variables (residual renal glomerular filtration rate, total weekly creatinine clearance, CRP, iPTH, iron adequacy, angiotensin system antagonist treatment, presence of polycystic kidneys) showed CRP and treatment with angiotensin system antagonists to be the most significant variables influencing IRE.Conclusion Our results show that systemic inflammation and angiotensin system antagonist treatment are the most important parameters affecting epoetin requirements in stable peritoneal dialysis patients.