Haemodiafiltration has “clear benefits” for kidney failure patients

A high dose of haemodiafiltration has “clear benefits” for kidney failure patients, according to a new study published in the New England Journal of Medicine.

The conclusion comes after the study found that mortality in patients with kidney failure was nearly a quarter (23%) lower among those treated with high dose haemodiafiltration compared to those treated with high flux haemodialysis.

Professor Andrew Davenport, a senior author of the study, said: “This is the first major step forward in many years and is good news for kidney disease patients and their families.”

Haemodiafiltration vs haemodialysis

When the kidneys can no longer do their job, dialysis is used to clean the blood by removing waste products, a function normally performed by the kidneys themselves. Around four million people are on dialysis worldwide.

Haemodialysis is the most common form of dialysis in which the patient’s blood is pumped through an artificial dialyser (kidney) by a blood pump.

Blood goes one way through the artificial dialyser and dialysis fluid, used to clean your blood, goes the opposite way through the dialyser; they do not mix. However, conventional dialysis is not good at removing large molecules from the blood.

Haemodiafiltration removes more water from the blood than haemodialysis, and this fluid is continually replaced with an ultra-pure electrolyte solution produced by the machine, which is then infused into the patient’s blood stream.

As a result, haemodiafiltration removes additional fluid and larger molecules, and therefore a higher level of toxins than conventional dialysis.

However, haemodiafiltration is not suitable for all patients due to the fact that it requires a higher blood flow rate to be effective. Patients with heart conditions, for example, who can only dialyse with low pump speeds may not be suitable.

Most modern dialysis machines able to perform both methods

Until now, no trials had proven that one method was more effective than the other. The CONVINCE trial therefore set out to compare high-flux haemodialysis and high-dose haemodiafiltration, with the aim of clarifying which method is superior.

The randomised trial included 1,360 patients, with roughly half (683 patients) treated with high-dose haemodiafiltration and the other half (677 patients) treated with high-flux haemodialysis three times a week.

Patients were followed up for 2.5 years (30 months), and an analysis of the results showed that all-cause mortality was 21.9% among those treated with high-flux haemodialysis, compared to 17.3% for those treated with high-volume haemodiafiltration. This 4.6% difference represents a 23% reduction in the risk of death.

The authors of the study are now calling for a switch towards haemodiafiltration, something that would be relatively easy considering most modern dialysis machines can perform either method.

Lead investigator, Professor Peter Blankestijn, said he hopes haemodiafiltration “can become the new standard.”

Professor Matthias Rose, a senior author of the study and expert in patient-reported outcomes, said work is now being done to find out more about patient perceptions of the treatment, with results expected later this year.

“In addition to clinical events, patient perception and thus reported outcomes are very important.  We are currently performing in-depth analyses of the extensive data on patient-reported outcomes that have been collected in the CONVINCE study,” she said.