Importance of iron saturation for erythropoietin responsiveness in chronic peritoneal dialysis

There is a great variation in erythropoietin (rHuEPO) requirements in peritoneal dialysis (PD) patients. Although some studies show the importance of higher iron saturation (FeS, > 20%) in hemodialysis patients for a maximal rHuEPO response, data on PD patients are scarce. We followed 38 stable PD patients for 5 months to evaluate the factors that may be responsible for variability in rHuEPO response. All patients received oral iron supplement and erythropoietin subcutaneously twice a week and were divided into three groups according to weekly rHuEPO dose (U/kg): Group I, < 50; Group II, 50-100; Group III, > 100. Hematocrit was maintained at a currently accepted level of 30%-36%. Iron saturation levels were 30.4 +/- 2%, 27.7 +/- 2.5%, and 21.7 +/- 2.5%, and rHuEPO doses were 37.3 +/- 2.4, 71.2 +/- 2.3, and 141.5 +/- 9.7 in Groups I, II, and III, respectively. There were no significant differences in age, sex, etiology of renal failure, parathyroid hormone, serum albumin, blood urea nitrogen (BUN), and creatinine between various groups. These data suggest that rHuEPO requirements are lower in PD patients with higher FeS. FeS may be a good indicator of rHuEPO requirement and responsiveness in PD patients. Achieving higher FeS than the currently accepted 20% may further decrease rHuEPO requirements in PD patients and have significant cost implications.