Comparison of intraperitoneal and subcutaneous epoetin alfa in peritoneal dialysis patients

Objective: To compare the efficacy of intraperitoneal (IP) and subcutaneous (SC) administration of epoetin alfa in patients receiving peritoneal dialy sis (PD). Design: A 32-week prospective, randomized, cross-over experimental design. Setting:Two university-based outpatient PD centers. Patients: Twenty adult PD patients receiving stable doses of SC epoetin alf a enrolled in the study. Thirteen patients completed 32 weeks of follow-up. Intervention: Patients were randomly assigned to receive either SC or IP ep oetin alfa at the start of the study. Dose adjustments were made to maintai n baseline hematocrit +/- 3 percentage points. Following 16 weeks of treatm ent, patients crossed over to the other route of administration for an addi tional 16 weeks. Intraperitoneal epoetin alfa was administered into an empt y peritoneal cavity for approximately 8 hours before resuming dialysis. End -of-study IP epoetin alfa doses required to maintain target hematocrit were given twice weekly (n = 1), once weekly (n = 11), or once every other week (n = 1). All patients received iron supplements to maintain or exceed pres tudy iron parameters. Main Outcome Measure: Prior to the study, the primary outcome measure was d efined as the difference in epoetin alfa dose between IP and SC administrat ion. Results:Thirteen patients completed the study. The area under the dosing-re quirement curve for IP epoetin alfa was larger than for SC administration ( p = 0.0029), and the slope of the 16-week dose-requirement curve was greate r for IP administration (p = 0.017), suggesting greater dose stability for SC administration. Paired analysis indicated greater IP intrapatient dose r equirements (p < 0.0001). The mean difference in SC versus IP doses was 500 0 +/- 1510 units per week. Some patients required escalating IP doses to ma intain target hematocrit values. Iron administration and iron stores were s imilar in both groups. Conclusion: Intraperitoneal epoetin alfa may be a suitable alternative for same patients for whom SC dosing is undesirable. Large IP versus SC dosing differences noted in a few patients are unexplained, but may result from in terpatient variability in IP epoetin alfa absorption. Intraperitoneal dosin g into an empty peritoneum can be done safely and effectively.