Postdilution on-line hemodiafiltration (OL-HDF) is considered the most efficient renal replacement treatment modality. Compared with conventional hemodialysis (HD), OL-HDF enables a better removal of middle molecular weight uremic toxins by combining convective and diffusive clearance. Although higher convection volume exchange has been associated with an increased survival advantage for dialysis patients, the mechanisms by which OL-HDF may improve outcomes remain unknown.
On the basis of improved toxin removal, a potential benefit of OL-HDF on nutritional status has been postulated. However, evidence on the effect of OL-HDF on nutritional status is scarce and at times conflicting. Some observational and interventional studies have suggested that OL-HDF is associated with improved nutritional parameters; others have found no effect; and one study even reported negative effects of OL-HDF on nutritional status. The majority of these observations come from cohort studies, non-controlled interventions and/or secondary analysis of controlled trials. Further, there are currently no data examining the plausible effect of postdilution OL-HDF on body composition. To clarify this important knowledge gap, this prospective, controlled, study evaluated the effects of high volume postdilution OL-HDF on nutritional status and body composition in prevalent HD patients.
