By Peter Laird, MD
Shortly after the onset of hemodialysis coming to the forefront as a viable life saving procedure in the 1960's, researchers hypothesized that daily dialysis would be the optimal treatment modality for artificial renal replacement therapy. Later, Dr. Carl Kjellstrand provided the theoretical physiologic justification for more frequent and longer duration hemodialysis with the "Unphysiology Hypothesis" in 1975.
The Rationale for More Frequent Hemodialysis – ‘Unphysiology’
In the early 1970s, Kjellstrand et al. [12, 13] investigated factors related the untoward effects of dialysis. They showed that large fluctuations in body weight, electrolytes, osmolality, and urea concentration were more important with respect to morbidity than concentrations of small uremic toxins or middle molecules. This led them to formulate the ‘unphysiology’ hypothesis which suggested that wide swings of solutes and fluids in the body were significant causes of morbidity in dialysis patients. Daily or continuous dialysis would more closely mimic the function of the native kidney by reducing the magnitude of solute and fluid oscillations and so would be expected to be superior to the usual intermittent dialysis regimens.
Interestingly, despite the long standing skepticism of quotidian dialysis protocols by the American nephrology community, researchers developing new dialysis technology such as the implantable artificial kidney, Victor Gura's WAK and other renal replacement devices in development all are in agreement with Dr. Kjellstrand's Unphysiology theory of more frequent and longer duration therapies. (here) Interestingly, even Wikipedia understands the underlying physiologic basis for developing these new renal replacement devices:
Need for a bioartificial kidney
Over 300,000 Americans are dependent on hemodialysis as treatment for renal failure, but according to data from the 2005 USRDS 452,000 Americans have end-stage renal disease (ESRD).[2] Intriguing investigations from groups in London, Ontario and Toronto, Ontario have suggested that dialysis treatments lasting two to three times as long as, and delivered more frequently than, conventional thrice weekly treatments may be associated with improved clinical outcomes[3] Implementing six-times weekly, all-night dialysis would overwhelm existing resources in most countries. This, as well as scarcity of donor organs for kidney transplantation has prompted research in developing alternative therapies, including the development of a wearable or implantable device.[4]
The fiscal reality of lack of available resources to implement universal access to quotidian dialysis has in my opinion greatly influenced not only government policy on hemodialysis funding and modality in the United States (here), I believe it has also over shadowed and influenced research on quotidian dialysis as well. Anyone that attends the Annual Dialysis Conference expects the lively debates between nephrologists who passionately support more frequent and daily hemodialysis as opposed to those who equally voice opposition to quotidian dialysis.
The Frequent Hemodialysis Network study group findings on short daily hemodialysis and nocturnal dialysis dialysis demonstrates this paradox clearly. The short daily hemodialysis arm of the FHN study showed positive outcomes for daily dialysis but it appears that only the negative findings of the nocturnal arm matter to the nephrology community despite the excellent methodology of the FHN short arm vs. the deficiencies of the FHN nocturnal arm. (here and here)
In March of this year, the nephrology community will gather once again at the Annual Dialysis Conference and debate the efficacy of more frequent hemodialysis vs conventional in-center treatment. An important part of those debates will involve the nocturnal FHN study:
Debate: More Frequent HD should be Recommended to Thrice Weekly HD Patients
- 8:00
There Is Enough Evidence to Support this Recommendation - Madhukar Misra, MD - 8:10
The Frequent Nocturnal Hemodialysis Randomized Controlled Trial Does Not Support this Recommendation
Alan Kliger, MD
Dr. Kliger will apparently sing a different tune speaking against more frequent HD than he did when he was appointed to the NxStage scientific advisory panel in 2011:
NxStage appoints Alan Kliger, MD to scientific advisory board
"The improved outcomes we saw in the FHN randomized controlled trial of daily dialysis should encourage patients and their physicians to consider daily hemodialysis as a serious option," said Kliger. "I''m excited to be involved with the team at NxStage, which is pioneering daily home dialysis with the System One in the U.S. and internationally."
More frequent hemodialysis is the hope of many patients today facing ESRD, but all too many nephrologists oppose the application of this simple therapy to their patients based largely on poor reimbursement from CMS. The despair of patients subjected to conventional in-center hemodialysis is evident with every single treatment where patients suffer from intradialytic hypotension followed by cramps, vomiting and passing out in centers that maximize profits at the expense of patient's outcomes. For over forty years we could have done better here in the United States and saved countless lives and further spared pain and suffering of patients yet we did not.
It is time for nephrologists to evaluate dialysis studies with a more rigourous eye towards poorly enacted methodology leading to questionable results. The FHN Nocturnal study is in my opinion a shameful publication that is fraught with such botched execution of its protocols that no one should uphold this as a reason to not engage more patients in daily dialysis. It is time to publicly admit the failure of the FHN nocturnal arm and declare this study null and void. Instead, just as nephrology dismissed the "insignificant" results of TIME in the NDCS (here) in 1981 leading to short dialysis duration and patient suffering and death, the FHN nocturnal study has the potential of setting daily dialysis to the back burner once again.
The NCDS dominated the optimal dialysis debate for decades until those that know and understand the power of more frequent and longer duration dialysis could produce the studies needed to bring the NCDS results into question. How many decades will the FHN nocturnal study dominate the debate on quotidian dialysis? Hopefully it won't given how flawed it is. However, the unjustifiable bias against daily dialysis continues today perhaps even more determined than it was before the short daily dialysis FHN study showed positive outcomes for more frequent dialysis. Observing this highly respected researcher using the FHN nocturnal study as a basis for opposing more frequent dialysis sadly leads me to despair the number of people who will not have access to the benefits of daily dialysis because of this.
The government support of research for new renal replacement therapy based on Dr. Kjellstrands "Unphysiology" theory is a source of hope but their hypocritical opposition to daily dialysis serves only to further despair. Dr. Kjellstrand was correct in 1975 and he remains correct today that more frequent and longer duration dialysis is the optimal dialysis strategy. Perhaps our only hope will be when these new technologies prove as cost effective as renal transplant. In that scenario, those that now vigorously oppose daily dialysis will likely become some of their most passionate supporters. We are left only with hope since it seems those that could make a difference today remain blind to our despair.
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