Haemodiafiltration reduces dialysis mortality in kidney disease

While high-flux haemodialysis is the more common therapy for people with kidney disease, haemodiafiltration is used in many centres. A meta-analysis of four randomised, controlled trials investigating haemodiafiltration compared with haemodialysis suggested a survival benefit when the former was delivered at a high dose. Confounding factors were present, however, and other studies have also been inconclusive.

To shed light on this uncertainty, the CONVINCE Investigators conducted a pragmatic, randomised, controlled trial at 61 European centres to assess the benefits and harms of high-dose haemodiafiltration compared with conventional high-flux haemodialysis. Participants were adults who had received haemodialysis for ≥3 months and were candidates for high-dose haemodiafiltration of ≥23 L/session. 

The primary outcome was death from any cause. Key secondary outcomes were cause-specific death, a composite of fatal or non-fatal cardiovascular events, kidney transplantation, and recurrent all-cause or infection-related hospitalisations.

From November 2018 to April 2021, 1360 participants were randomised, with 683 to receive high-dose haemodiafiltration and 677 high-flux haemodialysis. Median follow-up was 30 months and mean convection volume in the haemodiafiltration group was 25.3 L/session. The Kt/V value was higher in the haemodiafiltration group, and remained so during the trial.

Death from any cause occurred in 118 people (17.3%) in the haemodiafiltration group (7.13 per 100 patient-years) and in 148 people (21.9%) in the haemodialysis group (9.19 per 100 patient-years) (HR, 0.77 [95% CI, 0.65–0.93; P=0.005]). 

There was a suggestion of benefit for haemodiafiltration in both infection-related and cardiovascular deaths. Drawing conclusions from this is, however, complicated because COVID-19 as a diagnosis was added during the trial. 

The authors conclude that, in the trial population, the use of high-dose haemodiafiltration reduced the risk of death from any cause compared to conventional high-flux haemodialysis. However, they caution that the inclusion criteria may have resulted in participants being healthier than the general haemodialysis population and, due to lack of collection of participants’ race, the findings may not be generalisable to non-White people with kidney failure.

The full study can be read here.