Evidence for the Clinical Advantages of Predilution On-Line Hemodiafiltration

Abstract

Background: On-line hemodiafiltration (OL-HDF) is a rapidly developing dialysis modality that is expected to ameliorate the quality of life and survival rate of chronic dialysis patients. There are generally 2 types of dilution methods in OL-HDF: postdilution and predilution.

Summary: Postdilution OL-HDF is widely performed worldwide, whereas predilution OL-HDF accounts for >90% of all OL-HDF sessions performed in Japan. The reasons for the preference for predilution are to increase the substitution volume at a lower blood flow rate and to remove larger low-molecular-weight proteins (LMWPs). It is a unique Japanese concept for chronic dialysis to remove larger LMWPs, in so-called 'protein permeable dialysis', and ameliorate various uremic symptoms. Evidence for the beneficial effects of OL-HDF has not yet been confirmed, especially in the case of the predilution mode. The beneficial effects of predilution OL-HDF have recently been evaluated by 2 Japanese studies. A study by the Japanese Society for Dialysis Therapy (JSDT) found a clear survival benefit for all-cause mortality and cardiovascular mortality of predilution OL-HDF with a substitution volume >40 liters/session. A study by the Japanese Society for Hemodiafiltration (JSHDF) showed the noninferiority of predilution OL-HDF in relation to intradialytic hemodynamic stability compared with the postdilution mode. Key Messages: Further analysis of the JSDT and JSHDF studies may confirm the superiority of predilution OL-HDF over high-flux or super high-flux hemodialysis.