Online hemodiafiltration and medium cut-off dialyzers

In this Research in Brief, Karin Bergling, MD, PhD, Research Scientist at the Renal Research Institute (RRI), and Peter Blankestijn, MD, PhD, Medical Specialist at the University Medical Center in Utrecht, Netherlands, address a fundamental question in dialysis care: How do we move beyond diffusion alone to improve the outcomes for patients on dialysis?

Conventional high-flux hemodialysis efficiently removes small solutes. However, it is less efficient in removing middle molecular uremic toxins, which are linked to inflammation, cardiovascular disease, and reductions in quality of life.

To explore this, Bergling and Blankestijn synthesized mechanistic and clinical evidence of two convection‑enhancing therapies: Online hemodiafiltration (HDF) and the use of medium cut-off (MCO) dialyzers. They summarized available data on clinical outcomes, clearance, and patient-reported outcomes to aid in everyday clinical practice.

Large, randomized trials and meta-analysis show that online HDF, especially when the convection volume exceeds 23 liters, is associated with reductions in all‑cause, infection‑related, and cardiovascular mortality. For MCO dialyzers, studies clearly show an enhanced clearance of middle molecules, but the effects on clinical outcomes and patient-reported outcomes are scarce. Importantly, the convection component of this therapy cannot be measured or prescribed in clinical practice.

These findings support a shift toward more personalized dialysis prescriptions. To learn more, read the perspective paper in the American Journal of Kidney Disease: Beyond Diffusion: Clinical Perspectives on Online Hemodiafiltration and Medium Cut-Off Dialyzers.

Watch the full Research in Brief below: