By Peter Laird, MD
Kidney International recently published a study on daily dialysis alleging worse outcomes for patients on daily in-center dialysis as compared to conventional in-center thrice weekly dialysis. The authors noted that this was a different outcome than prior observational dialysis studies on more frequent and longer duration strategies.
Those receiving daily hemodialysis had a significantly higher mortality rate than those receiving conventional hemodialysis (15.6 and 10.9 deaths per 100 patient-years, respectively: hazard ratio 1.6). Similar results were found in prespecified subgroup and sensitivity analyses. Unlike previous studies, we found that in-center daily hemodialysis was not associated with any mortality benefit. Thus, decisions to undertake daily hemodialysis should be based on quality-of-life improvements, rather than on claims of improved survival.
The researchers conclude that their study is the most conclusive and best evidence on mortality of daily dialysis in-center. However, simply reviewing their methods and results brings into question several areas of concern with this latest publication.
First, the most obvious data needed to compare the patients in this cohort is the clinical indication for why they were on daily dialysis in the first place. While daily dialysis at home is a utilized in the United States and more widely in Europe and Australia, even in those nations, daily dialysis in-center is not ordinarily utilized without specific clinical reasons. In America, many patients who are failing on conventional thrice week therapy often advance to four times a week treatments or more as a rescue strategy. Incredibly, this study failed to gather any data on why patients were on daily dialysis in-center and they indicated informally that rescue may have been an operative indication:
Most importantly, we do not have any information as to why daily hemodialysis was prescribed to individual patients in this study. If daily hemodialysis was prescribed as a ‘rescue’ option, patients selected for this therapy may have been sicker than those maintained on conventional dialysis. Some French patients may have been selected in this way (personal communication, CC and RG).
In addition, the short daily group had twice as many grafts compared to the conventional group and 30% of the short daily patients had no access data at all. Given the significant risk of death from AV grafts compared to fistulas, this could lead to significant confounding bias. Other data lacking in this study included no documentation of residual renal function, severity of co-morbid disease or socioeconomic factors, all of which are known predictors of survival.
In addition, a secondary analysis of the FHN short daily and nocturnal studies by the same lead author focused on access issues speaks negatively of daily dialysis in yet another study:
In conclusion, frequent hemodialysis increases the risk of vascular access complications. The nature of the AV access repairs suggests that this risk likely results from increased hemodialysis frequency rather than heightened surveillance.
Many are already discouraged from recent studies and negative commentaries on daily dialysis. Others that know and understand the benefits of daily dialysis and will simply ignore this latest study:
Studies like this, in my humble opinion, do more harm than good. Some doctors would potentially be put off by this risk of access problems and not recommend more frequent dialysis for their patients. The benefits of the modality are mentioned only in passing and the entire focus of the paper is access problems. This may be all right when you look at it purely from a statistical perspective. But I am really worried that the paper might have just taken daily dialysis off the menu for some people about to get onto dialysis.
That is sad, indeed.
I agree with Kamal Shaw except in one regard. I don't believe that this author in two separate studies has truly proven that more frequent hemodialysis has higher complications and higher mortality. Yes, indeed, that is the conclusions of her two articles, yet can we discount all of the positive articles that have come before? A noted deficiency of the FHN articles is that they did not report whether they used constant site cannulation, better known as buttonhole cannulation which has a lower risk of stenosis and aneurysm, but may increase infections in an in-center setting.
Blood flow rates were not noted in either of these studies as well. Unfortunately, a common practice of many dialysis nurses with short daily dialysis is to significantly increase the blood flow rate to the maximum allowable levels. This is a known cause of access complications that is entirely preventable, but many nurses and patients increase the blood flow rate to improve solute clearances and reduce the time of dialysis. Unfortunately, this data is lacking as well.
I have now completed six full years of hemodialysis and by God's grace and mercy, I have yet to have any access complications. I am now completing nearly 4 years on continuous home hemodialysis with 5-6 cannulations each week. More than once, dialysis professionals have commented that my fistula is the "prettiest" fistula that they have seen.
It is clear when you evaluate the causes of access failure and complications that technique is paramount to assuring reduced adverse events. Taking care of an access requires time that most dialysis technicians simply do not have. It takes me about 20 minutes to remove my scabs, control any bleeding and place betadine, let it dry and remove the excess with alcohol pads prior to inserting my own needles. Most techs simply apply the disinfectant, wipe off any excess and stick a needle into the fistula in less than a minute for both, perhaps two minutes in some cases.
Buttonhole cannulation does not lend itself to that type of rapid access cannulation. What puzzles me the most is the number of nephrologists who actively seek to prove daily dialysis inferior. Is it not time that we enter the rest of the realm of medical practice where we seek to avoid complications, improve procedures and improve outcomes? Sadly, in my opinion, much more effort is generated to discouraging patients from seeking home daily hemodialysis than promoting this wonderful modality.
In my opinion, having God's blessing of no complications from my dialysis to date, frequent daily hemodialysis is easy and safe to administer. I have no doubt that the technical difficulties that in-center patients suffer causing many of these complications are easily correctable but they must have time to do so. It never ceases to amaze me how little the so called dialysis professionals in-center understand about home hemodialysis and commonly used home dialysis techniques.
The better question to answer and promote is why is it that some patients can secure their access without any significant complications for decades, yet some in-center patients suffer frequent episodes of these "common" complications. It is with great regret that I have come to understand that a large majority of "common" dialysis complications are in reality iatrogenic in nature. Access complications appear to be no different.
I would hope that the story of dialysis will one day include a marvelous period of reawakening of how to do things better. The intensive care central line infection rates ravaged patients throughout America until a wise doctor in Johns Hopkins realized that we could improve the technique of inserting and caring for central lines. (here and here) Today, using a simple protocol for all of these procedures, infetions of a central line is now consider a "never" event since it should never occur. This is a prime example of improving the technique of a procedure to eliminate "common" infections which in the end analysis were iatrogenic in nature.
The dialysis industry has yet to embark on the same quest of excellence that our colleagues in other specialities have embraced decades ago. I understand that my risk of infection and complications is quite low even with daily dialysis due to adherence to strict techniques to eliminate potential complications. I am not alone in that many home hemodialysis patients have never had any major complications for years either. Is it not time to start looking at how to prevent complications instead of spending so much time and energy trying to denigrate optimal dialysis?
Perhaps I am simply asking too much but I don't believe so. With my understanding of the benefits of daily dialysis, I wonder when will the American nephrology community learn how to best apply simple techniques to routine dialysis practice that in the end is not costly at all and will save patients suffering, death and pain while reducing secondary treatment costs substantially.
Yes, daily dialysis in the hands of current technicians may indeed be dangerous. Daily dialysis in my hands is easy, safe and effective by strict protocols much in the same fashion as the central line bundle. I wish I could be there for every single patient to apply my own tried and true hygiene and cannulation techniques I have learned from many wise people such as Stuart Mott, but alas, I can't nor can Stuart. Why is it that select individuals can perform these procedures with minimal complications, yet the industry in general cannot? I believe I know the answers to that question, but the industry is not even asking that question. Perhaps that is the biggest problem of all.