Hemodiafiltration on American shores
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Healio | Nephrology News & Issues: Is the evidence that HDF is medically better than traditional HD at a tipping point?
Thomas A. Golper, MD: There have been several randomized controlled clinical trials using HDF with differing criteria, populations studied and procedural strategies that have offered differing outcomes. The most definitive was the multinational CONVINCE trial, which mandated a specific procedure of high convective volume substitution. These trials have been reviewed and compiled in several meta-analyses and commented upon in editorials.
All these studies on HDF involve prevalent patients. There are many more eligible prevalent patients to recruit for these studies than incident patients but testing use of conventional HD vs. HDF should start as early as possible in end-stage kidney disease. Starting the trial in incident patients is even more likely to discern a difference. As I wrote in a New England Journal of Medicine editorial about the CONVINCE trial:
“We do not know the full cascade of metabolic changes that occur in a person when kidneys fail. However, we observe multisystem progressive deterioration as kidney function declines ... Kidney replacement therapies do not reverse all the ravages of uremia. Compared to high flux HD, high convective volume HDF may more effectively slow deterioration and improve survival.”
Healio | Nephrology News & Issues: Will nephrologists who have not previously used HDF acquire the necessary experience?
Thomas A. Golper, MD: I have concerns about this, based on my experience with home dialysis professional education involving the intense immersion course (Home Dialysis University). More than 100 2.5-day sessions have taken place since 1998. In some years, the course was taught to two-thirds of second-year U.S. nephrology fellows.
In 2023, the American Society of Nephrology partnered with Home Dialysis University and provided partial scholarships for fellows to participate. The Advancing American Kidney Health initiative incentivizes the use of home dialysis. Despite these efforts toward education and other motivations, the uptake of home dialysis use is still sluggish. Beth Piraino, MD, once articulated (I am paraphrasing), “Why would doctors use or recommend a therapy that they know so little about?” This has made me skeptical that HDF education will be done right.
Healio | Nephrology News & Issues: Will the cost of converting to HDF preclude its utilization?
Thomas A. Golper, MD: The equipment for HDF differs from the HD machines used today in the United States. The good news is that many manufacturers make them, albeit only Fresenius currently has FDA approval. As current HD machines wear out, will we replace them with HDF machines? We could but recognition of HDF benefits must be addressed first.
The higher costs for HDF have been discussed but these arguments have not yet won the day. An interim suggestion is that currently available medium cutoff membrane (MCO) dialyzers might be a transitional step to apply from HD to HDF. MCO dialyzers use would increase a session cost by about $9, but even that has been an obstacle.
The currently underway British H4RT trial also recruited prevalent patients but is using National Health System (NHS) information to explore many more outcomes that could be achieved by CONVINCE, such as mortality from all-causes as well as cause-specific; hospital admissions related to cardiovascular or infection events; quality of life including time to recover; indirect effects such as laboratory indicators of inflammation, anemia and bone mineral disorder management; costs and cost-effectiveness; incremental cost-per quality-of-life years gained; and environmental impact. Britain’s NHS is as much under cost constraints as any health system, so its participation will be welcomed and informative worldwide.