Emerging Clinical Evidence on Online Hemodiafiltration: Does Volume of Ultrafiltration Matter?

Abstract

Online hemodiafiltration (OL-HDF), first described in 1985, is today a widely prescribed treatment modality for end-stage chronic kidney disease (CKD) patients. Other than in the United States, prescription of the treatment modality is widespread with a steady increase since its inception. Indeed, in Western Europe, more CKD patients receive OL-HDF than peritoneal dialysis, hitherto the second most prescribed therapy after conventional hemodialysis. The rise and success of OL-HDF can be attributed to diverse clinical advantages that have been documented over the last two decades. Numerous publications attest to the beneficial effects of OL-HDF in terms of removal of a broad spectrum of uremic toxin, anemia control, phosphate reduction, increased hemodynamic stability and blood pressure control and less dialysis-related amyloidosis, to mention just a few. Significantly, the improvement in these conditions is considered to contribute to improved patient outcomes. Despite the extended worldwide clinical experience, elaborate scientific validation of the principles of the therapy and technical innovations that facilitate its prescription, a point of contention is whether OL-HDF leads to a reduction of mortality rates. A number of observational and retrospective analyses have indicated a survival benefit, while prospective investigations involving small numbers of patients but nevertheless specifically addressing survival have further supplied evidence of improved survival with OL-HDF. The quest for large-scale, multicenter prospective randomized controlled trials examining patient survival led to the CONTRAST and the Turkish OL-HDF trials. Both trials have been concluded and published recently. In this chapter, we document and assess the key investigations that have examined the impact of OL-HDF on patient outcome and survival. Based on the findings of previous analyses and of the two recently concluded trials, it appears that the volume of convection appears to be decisive towards the survival benefit accredited to OL-HDF. We consider the implications of this new evidence.

Effect of Increasing Dietary Fiber on Plasma Levels of Colon-Derived Solutes in Hemodialysis Patients

“…and/or duration of treatment and to increasing solute clearances during treatment (19,20). A possible complementary means to improve dialysis treatment is to suppress solute production.…”

Dialysis-related amyloidosis: challenges and solutions

“…34 In fact, several studies have demonstrated that the serum levels of b2M are lower in patients treated with high-flux biocompatible membranes. 61,62 Moreover, as shown by Furuya et al, the use of high-purity dialysate with lower endotoxin level than the conventional dialysate is beneficial during HD treatment because of reduction of serum b2M, pentosidine, C-reactive protein, and IL-6 which probably accelerate amyloid deposition. 63 Since both hemofiltration and hemodiafiltration are able to remove b2M significantly, some studies have reported a lower incidence of CTS in patients treated with these two dialysis methods; however, a clear benefit of these two dialytic techniques versus biocompatible high-flux HD performed at high blood flow rate has not been demonstrated.…”

Cardiovascular Risk Factors in End-Stage Renal Disease Patients: The Impact of Conventional Dialysis versus Online-Hemodiafiltration

“…One possibility is that the delivered dose of HDF was not sufficient, considering that in two of the larger trials [85,88], a positive association between higher convective volume replacement and better relative outcomes was observed. Indeed, the importance of convective volume to improve survival of OL-HDF patients has been highlighted [101]. Higher convection volumes in OL-HDF were associated with higher patient's survival; however, results varied across different ways of standardization for body size, suggesting that further studies should consider body size [102].…”