This post summarizes a session I attended at the National Kidney Foundation Spring Clinical Meeting in New Orleans on May 8, 2026.

Presenters: Deborah Clegg, Sagar Nigwekar, and Steven Spiegel

For the past decade, there has been little improvement in mortality outcomes for people receiving dialysis. One potential reason may be the relative lack of major advancements in dialysis care. There is growing interest in whether newer dialysis modalities, such as hemodiafiltration (HDF), may help improve outcomes for people living with kidney failure.

What is hemodiafiltration (HDF)?

Traditional hemodialysis primarily relies on diffusion and is effective at removing small solutes. Hemofiltration, on the other hand, relies on convection and is more effective for removing larger middle molecules.

Hemodiafiltration combines both diffusion and convection. Typically, this results in ultrafiltration of approximately 25–35% of the dialyzed blood volume.

How does clearance from hemodiafiltration compare to hemodialysis?

Compared to conventional hemodialysis, hemodiafiltration is associated with:

• A 10–15% increase in small molecule clearance (including urea and phosphorus)
• A 40–50% increase in middle molecule clearance
• A 10–15% increase in large molecule clearance
• A 5–10% decrease in clearance of protein-bound molecules

What is filtration fraction?

Filtration fraction describes how much fluid is removed from the blood during the dialysis process. The target filtration fraction is typically 25–30%.

If the filtration fraction becomes too high, hemoconcentration can occur, increasing the risk of clotting. Hemodiafiltration appears to provide better control of filtration fraction compared to conventional hemodialysis.

What factors impact hemodiafiltration clearance?

Several factors influence HDF clearance:

• Molecule size and membrane pore size
• Ultrafiltration rate
• Blood flow rate

The dialysis bath itself does not appear to significantly impact clearance.

How does hemodiafiltration impact hemodynamics?

Hemodiafiltration is often associated with improved hemodynamic stability, potentially related to differences in body temperature regulation and osmotic gradients during treatment.

Albumin is generally preserved during HDF, which may help reduce intradialytic hypotension and muscle cramping by supporting fluid movement between body compartments.

What are the key studies related to hemodiafiltration?

One of the key recent studies was the CONVINCE trial.

Earlier HDF studies initially failed to demonstrate clear mortality benefits. However, post-hoc analyses suggested improved outcomes among patients who achieved convective volumes greater than 23 L per session. These findings helped set the stage for the CONVINCE trial, which specifically aimed to achieve convective volumes above this threshold while evaluating clinically meaningful outcomes.

What were the key findings of the CONVINCE trial?

Key findings included:

• Participants achieved an average convective volume of 26 L
• Kt/V improved by approximately 0.15
• Mortality rates were reduced by 23%
• Declines in quality of life appeared to occur more slowly compared to conventional hemodialysis

In the real world, can convective volumes greater than 23 L be achieved?

Data presented from a real-world dialysis center suggested that:

• 81% of participants achieved convective volumes >23 L
• Treatment time and blood flow rates were important factors in reaching this target
• These results were achieved in patients using both catheters and fistulas

Additional observations from the center included:

• Greater use of K3 baths compared to K1 or K2 baths
• Lower bicarbonate concentrations, typically around 31–32 mmol/L

How does fluid removal compare with hemodiafiltration?

Fluid management appeared to improve with HDF. A greater percentage of patients were able to finish treatment within 1 kg of their target weight while also achieving a post-dialysis systolic blood pressure below 140 mmHg.

Is hemodiafiltration better or worse for the environment?

The session presenters suggested that HDF may have environmental advantages, including reduced plastic use and substantial water savings.

What are staff perceptions of hemodiafiltration?

Dialysis unit staff reported that HDF was associated with improved workflow and greater staff satisfaction.

What are patient perceptions of hemodiafiltration?

The session included a patient partner who described feeling significantly better following dialysis treatments since transitioning to hemodiafiltration.

Are there any contraindications for hemodiafiltration compared to conventional hemodialysis?

No major contraindications were discussed during the session. However, if units are implementing HDF gradually, patients experiencing frequent cramping or intradialytic hypotension may potentially benefit the most from earlier transition to this therapy.

Key Takeaways

• Hemodiafiltration may improve mortality outcomes and slow declines in quality of life for people living with kidney failure.
• Achieving a convective volume target greater than 23 L per session appears important for maximizing benefit.
  • Treatment time and blood flow rates are key factors in reaching this target.
• Hemodiafiltration appears to be associated with improved dialysis tolerance and hemodynamic stability.
  • This may particularly benefit patients who experience cramping or intradialytic hypotension during conventional hemodialysis.
• Hemodiafiltration may also offer environmental and workflow advantages compared to conventional hemodialysis.

Overall, hemodiafiltration is emerging as a promising advancement in dialysis care, though further research and real-world implementation data will continue to shape how broadly this therapy is adopted.