A Catalan study shows that a world-pioneering dialysis technique reduces patient mortality by 30%

The technique started in Catalonia in 2007 and by 2011 it was practiced on 40% of patients with renal failure. The Catalan Health Ministry hopes to cover 100% of the cases within the next 5 to 10 years. In the United States it started being used a year ago as they were waiting for clinical results to expand its use. Now, a clinical study on 900 patients from 27 different Catalan centres has proved that the technique reduces mortality by 30% on patients with kidney failure within the first three years. In addition, it improves quality of life, reduces hospitalisations by 22% and it also makes hypotension episodes drop by 28%.

CNA / Elisenda Rosanas

February 15, 2013 09:10 PM

Barcelona (ACN).- A clinical study on 900 patients with renal failure from 27 different Catalan centres has proved that a world-pioneering dialysis technique reduces mortality by 30% within the first three years. The technique known as on-line hemodiafiltration (HDF-OL) started being implemented in Catalonia in 2007 and by 2011 it was practiced on 40% of patients with renal failure. The technique is based on the application of greater pressure on the blood to liberate it from toxins more effectively. It is more expensive than the current dialysis method but it improves the patient’s quality of life, reduces mortality and significantly reduces secondary problems and the derived hospital costs. In light of the study, the Catalan Health Ministry hopes to cover 100% of the cases within the next 5 to 10 years. Besides the 30% mortality reduction, the study showed that it reduces hospitalisations by 22% and it also makes hypotension episodes drop by 28% thanks to the exchange of a higher volume of blood, which also results in patients feeling better after the treatment. The HDF-OL is already used in some other Autonomous Communities in Spain and in other countries. In the United States the technique started being used a year ago as they were waiting for clinical results before expanding its use. Some scientific studies had already been published in the Netherlands and Turkey, but without a clear improvement in results compared to the previous treatment. The Catalan study has received significant media attention, particularly in the States where the new dialysis technique has created some controversy.


The on-line hemodiafiltration is a new technique which has evolved from regular dialysis, improving its results and the patients’ quality of life as a Catalan study has just shown, ending the controversy over the two treatments. The study was based on 900 patients with renal failure from 27 centres spread throughout Catalonia and it was coordinated by Barcelona’s Hospital Clínic. Doctor Francesc Maduell, Head of the Dialysis Section within Hospital Clínic’s Nephrology Service, headed up the study.

The main change from the regular treatment is the incorporation of a convection process, a process applying additional pressure onto the blood extracted. This makes the new system able to exchange a volume ranging between 15 to 30 litres of blood per session – as the blood goes through the system several times. In the regular dialysis treatment, between 2 to 3 litres of blood are “cleaned” of toxins. According to Francesc Maduell, many more ureic toxins are eliminated per dialysis session, which bring many advantages to the patients.

Maduell explained that the new method requires greater security controls and safer filters than with the previous dialysis technique, although the same machines can be used. Maduell insisted that the technique is not more aggressive than the original one. In addition, it lasts the same amount of time (around 4 hours per session) and also has to be applied three times per week. Therefore, the patient does not perceive the change regarding the application of treatment, but will perceive the results, as they feel better afterwards and tolerate it better. This also results in having to take a smaller amount of medication.

Patients feel better

The Chairman of the Catalan Kidney Patients’ Association, Antoni Tombas, has confirmed the improvement. Tombas emphasised that his recovery when he leaves the dialysis room “is much quicker” now and he does not need to rest afterwards. “You feel better and stronger”, he added. He explained that they do not feel dizziness or cramps after the session. Therefore, he can carry on with his daily life much more easily. He thinks that the improvement “is obvious”.

However, as Doctor Maduell explained, the advantages go beyond this. Not only is mortality reduced in general terms by 30%, but mortality linked to cardiovascular causes drops by 33% and that derived from infections by 55%. Furthermore, Maduell stressed that the number of hospitalisations due to complications or consequences of kidney failure is reduced by 22%, which results in saving money within the entire healthcare system. On top of this, the number of hypotension episodes plummets by 28% during the treatment. The head of the Hospital Clínic’s Dialysis Section emphasised that, on one hand the treatment is more expensive because greater controls and more filters are needed. However, on the other hand, it also saves money by reducing hospitalisations, reducing associated medication, decreasing mortality and helping patients to get back to their daily life more quickly.

The new technique started being implemented in Catalonia in 2007 in a very small cohort of patients. Gradually the percentage increased until it had reached 40% of all the dialysis patients by the end of 2011. After the results of the study, the Catalan Health Ministry is aiming to make this treatment the first recourse for all patients needing dialysis. The study brings the scientific evidence needed to generalise the treatment.