CONVINCE Study

CONVINCE is a study funded by the European Union’s Horizon2020 program. We bring together companies and universities from all over Europe to try to find a definite answer to the question whether haemodiafiltration is a better treatment for kidney failure than the current standard of haemodialysis. To do that, we randomly assign study participants to dialysis or HDF, and then follow them for two years to see which group has the better outcomes.

In 2016, 121 patients with kidney failure per million of the population (pmp) started treatment by dialysis and transplantation in Europe ; ranging from 29 pmp in the Ukraine to 251 pmp in Greece. Almost two-thirds of these patients were men, over half were aged 65 years or older and almost a quarter had diabetes mellitus as their primary kidney disease. 84% of patients started with haemodialysis.

At the end of December 2016, the total number of patients with kidney failure treated by dialysis and transplantation was 823 pmp, ranging from 188 pmp in the Ukraine to 1906 pmp in Portugal. In 2016, the number of men treated for kidney failure was higher for men (11381 pmp) than women (101 and 827 pmp).

The majority of patients with chronic kidney disease who are treated with renal replacement world-wide are treated by haemodialysis. During a haemodialysis treatment, blood from the patient is pumped into a dialyzer, which contains multiple fibres. Blood passes through the centre of the fibres and dialysis water flows on the outside of the fibres, so that the waste products of metabolism pass by diffusion, along a concentration gradient from the blood into the dialysis water, so cleaned blood is returned to the patient. Diffusion is very good at removing small molecules, but not so good at removing larger molecules. Haemodiafiltration uses the same dialysis machine and dialyser, but as blood flows through the fibres, a force is applied and sucks water from the blood. This action also clears molecules in the water sucked through the fibre membrane.  This movement of molecules is called convection, and increases the number of larger molecules removed. 

So the key difference between haemodiafiltration and haemodialysis, is that haemodiafiltration removes more larger molecules than haemodialysis. Whether removing more larger molecules is better for patients remains to be determined, which is why we have the CONVINCE study to try to answer this question. Although removing more larger molecules would appear to be better, dialysis is an unselective treatment, so although haemodiafiltration may remove more potentially harmful molecules, it could equally remove more essential molecules, which could be harmful, and this is why we need to decide whether one treatment for kidney dialysis patients is better than the other. Studies so far gave no reason at all for any safety concern.

Haemodialysis (HD) treatment is the current standard of care for the vast majority of patients with ESKD. Despite it being a good treatment, the risk of fatal and non-fatal cardiovascular disease, for infections, hospitalisation still remains high, and we should try to reduce that high risk whenever possible. Also, HD patients are still troubled by a low quality of life, and improvement of the quality should be an aim of every health professional.

We need to develop better treatments for people with kidney failure, because they often feel tired and exhausted with the existing therapy options and often feel they have little opportunity to address these concerns with healthcare professionals in a structured manner. CONVINCE introduces new and interactive questionnaires that will allow patients to share when they feel better and experience fewer symptoms. It will be possible to determine what aspects of care positively influence health perception and health-related quality of life, allowing patients to actively participate in conserving their health and allowing physicians and nurses to provide more adequate support.

Our main outcome is quite straightforward: over the duration of the trial (at least two years), we track the survival rate of study participants to compare groups in HD and HDF treatment conditions. Additionally, we ask participants in both conditions to fill out interactive questionnaires about how they feel in relation to their treatment and the disease, and their quality of life in general, so we can find out whether participants feel better using HDF compared to standard hemodialysis.

Participants will be asked questions about how they feel using the PROMIS® approach. Each time a question is answered, the system automatically selects an appropriate follow-up question. For example, a study participant who answers that she is comfortable with walking up a flight of stairs may not need to be asked if she can get out of bed on her own. Instead, the survey tool may ask if she runs errands by herself regularly. The system may also decide that no additional question is needed to get a good overview of her health situation at all, thereby reducing the burden of answering too many questions.

In the course of the trial, the electronic questionnaires can only be filled out on specific tablet computers in the participating centers. Once we know that the survey forms work well in the study, we will endeavor to make them available on any device in regular patient care, including personal smartphones. 

We recruit participants in a large number of different dialysis centers in 8 different countries, France, Germany, Hungary, The Netherlands, Portugal, Romania, Spain, and United Kingdom.

The dialysis sites included in our study select the participants who meet our inclusion criteria, and approach them to ask whether they are willing and able to join the study.

If you are treated in a participating centre and qualify for inclusion, staff will approach you.

At present, CONVINCE is planned to be finished in the year 2023 with clear end reports to be published in major scientific journals. The course of the trial can be followed through our website convincetrial.eu.