- Blankestijn PJ et al. CONVINCE Scientific Committee Investigators. Effect of Hemodiafiltration or Hemodialysis on Mortality in Kidney Failure. N Engl J Med. 2023 Aug 24;389(8):700-709. DOI: 10.1056/NEJMoa2304820.
Haemodialysis is still the most widely used dialysis procedure. Of the approximately 4 million people worldwide who have to undergo dialysis, it is used for 80 per cent of patients. However, this could change following the groundbreaking study (DOI: 10.1056/NEJMoa2304820).
The multinational research project, which was funded by the European Commission Research & Innovation, involved 8 partners at 61 centres in 8 European countries. It included 1,360 patients with end-stage renal disease (stage-V chronic renal failure) who had been receiving high-flux haemodialysis for at least 3 months. They were allocated in a 1:1 ratio by block randomisation, stratified by centre, to one of the treatment groups: either continuing haemodialysis or switching to haemodiafiltration.
The primary endpoint was mortality (death from any cause). In addition, cause-specific mortality, cardiovascular events, renal transplantation, and recurrent hospitalisations were investigated. All data were collected as part of routine clinical practice. The median follow-up period was 30 months.
During the study period, a total of 118 patients (17.3 per cent) died in the haemodiafiltration group (7.13 events per 100 patient-years) and 148 patients (21.9 per cent) in the haemodialysis group (9.19 events per 100 patient-years). This means that the risk of death in patients treated with haemodiafiltration was 23 percent lower than with standard haemodialysis treatment (hazard ratio, 0.77; 95 percent CI 0.65 to 0.93; P=0.005).
Of the total of 266 deaths, 68 (25.6 per cent) were attributed to cardiovascular disease, 26 (9.8 per cent) to Covid-19 and 56 (21.1 per cent) to other infections. While no differences were found in cardiovascular mortality between the two groups, infection-related deaths including Covid-19 were also reduced in the haemodiafiltration arm (hazard ratio, 0.69; 95 percent CI, 0.49 to 0.96).
Although some of the previous studies comparing the two dialysis procedures have already come out in favour of haemodiafiltration, they had methodological limitations that have so far prevented a reliable conclusion. Now, for the first time, valid data is available that demonstrates a survival advantage of the newer procedure.
The study authors are already thinking about putting it into practice. This would not change much for patients: They would still have to undergo haemodiafiltration dialysis three times a week for 4-5 hours at a time.