Comparison of Post- and Pre-dilutional Hemodiafiltration in Hemodialysis Patients

Hemodiafiltration (HDF) is a choice of treatment modalities for patients with end-stage renal disease. Hemodiafiltration, combining diffusion and convection, may increase removal of large and middle molecule uremic toxins comparing to conventional hemodialysis. The techniques of hemodiafiltration include pre-dilution and post-dilution according to the infusion site of substitution fluid. Post-dilution HDF is most widely used because of higher removal rate of uremic toxins. However, hemoconcentration and clotting of membrane limit its further clearance of toxins. Pre-dilution may preserve membrane permeability and maintain hemodynamic status. Although lower clearance of small molecule uremic toxins, one study in Japan showed survival benefits of pre-dilution HDF, comparing to post-dilution HDF. The aim of this study was to compare pre-dilution and post-dilution HDF in terms of their clinical and biological parameters and clearance of uremic toxins by using cross-over study design.