E Vilar et al. Optimizing home dialysis: role of hemodiafiltration. Contributions to Nephrology, 2011;168:64-77.

Over the last 40 years the technical obstacles, which prevented a convective contribution to diffusive dialysis, have been overcome. Hemodiafiltration represents a natural evolution of intermittent extracorporeal blood purification and the technology is now available to offer this as standard treatment in-center. Vilar and colleagues reviewed the literature. The first randomized control trial of dialysis dose (National Cooperative Dialysis Study) showed that for three times weekly dialysis a critical level of urea clearance was necessary to ensure complication-free survival, the effect being noticeable by 3 months. Following this, observational studies suggested that higher doses improved longer-term outcome. In a second large randomized controlled study (HEMO), higher small molecule clearance did not further improve outcome, but high-flux membranes, which permitted enhanced clearance of middle molecules, appeared to confer survival benefit in patients who had already been on dialysis > 3.7 years. Recently, outcomes from the Membrane Permeability Outcome study confirmed a survival benefit of high-flux membranes in high-risk patients. These studies indicate that in the medium term survival is critically dependent on achieving a minimum level of small solute removal. However, longer-term survival (measured in years or decades) not only requires better small solute clearance but also enhanced clearance of middle molecules, the toxicity of which manifest over longer time scales.

WHAT THE STUDY MAY MEAN TO YOU AS A HEALTH CARE PROVIDER: The rationale for convective treatment is strongest in those patients who have the greatest potential for long-term survival. Patients who opt for self-care at home to allow frequent dialysis generally are constituents of this group. Hemodiafiltration is likely to become standard therapy in-center and in the home.

WHAT THE STUDY MAY MEAN TO YOU AS A HEALTH CARE PROVIDER: Use of self-management skills, such as many patients are already performing, seems to have been highly useful in hemodiafiltration. This approach to managing kidney disease is likely to be of greater value in the future.