The effect of hemodiafiltration with on-line endogenous reinfusion (on-line HFR) on anemia: design of a European, open, randomised, multicentre trial

The lack of backfiltration reduces plasma levels of C-reactive protein and interleukin-6. Paired filtration dialysis is the hemodialfitration technique that abolishes backfiltration. By physically separating convection from diffusion, it allows pure ultrafiltrate to be available during the entire session, so the ultrafiltrate can be regenerated and used as infusion fluid. On these premises, we have developed a European, open, randomised, multicentre study aimed at evaluating the effect of hemodiafiltration with on-line endogenous reinfusion (on-line HFR) on anemia. At least 130 chronically uremic hemodialysed (bicarbonate hemodialysis) stable patients with mild anemia (Hb between 9 and 11 g/dL) will be enrolled and normalized for iron stores by concomitantly repleting iron deposits (if ferritin <300 mu g/L) and reducing the dose of erythropoietin to maintain Hb values within the range at enrollment (9-11 g/dL). Patients will be included in the study, randomized to the two treatments (test treatment: online HFR; control treatment: hemodiafiltration or modified forms) and followed up for nine months. Iron stores will be maintained within normal levels and the dose of erythropoietin will be kept constant. The primary question and response variable will be the mean monthly changes in hemoglobin levels over the period of nine months. As secondary questions and response variables, we will measure the nutritional status using a subjective global assessment, protein catabolic rate, urea generation rate and the dietician's assessment, serum concentrations of vitamins A, C, E and serum C-reactive protein