That Strange Dialysis Conundrum - Selection bias .. 'Cherry picking' .. or Optimum HD for those who can

This blog post was made by Dr. John Agar on October 2, 2014.
That Strange Dialysis Conundrum - Selection bias .. 'Cherry picking' .. or Optimum HD for those who can

Dialysis – indeed, the whole modality realm of renal replacement – presents us with a strange conundrum.

We just know that dialysis is—for almost all except, perhaps, the very old, frail or infirm—a better option than conservative therapy for both longevity and wellbeing . But…has there ever been a randomized control trial (RCT) of dialysis vs. conservative therapy to “prove” this? No, there has not—nor will one ever likely be done.

We just know that transplantation—for the young, fit and less co-morbid—offers better wellbeing than does dialysis. But…has an RCT ever confirmed this? No, nor are we likely to conduct one, despite several recent papers that favorably compare the survival outcome of “matched” patient cohorts of home extended hour and frequency dialysis to those of deceased donor transplantation (1).

But then, when it comes to comparing the various modalities of dialysis, we lose the “certainty” plot. Suddenly, we seem not to know , or accept, which dialysis modality—or, more particularly, what modality setting: facility or home —yields the best outcomes. This is despite the wealth of multi-national, all-in, registry data and observational studies that support superior outcomes from home-based therapies—especially home hemodialysis. Aha, they say, the successful outcome studies in home dialysis are all because of “selection bias”!

Despite warmly embracing the superior outcomes of transplantation, as we should, we rarely acknowledge that the renal transplant cohort is one of the most highly medically selected groups on the planet. Every orifice is inspected, every organ is assessed, every biochemical, bacteriological and immunological cranny is probed. On the other hand, dialysis patients are, broadly, those who are deemed unfit or unacceptable for transplantation, though a minority will be transplant candidates awaiting a donor kidney. But, we do advise transplantation wherever possible and feasible…because it is “offering the best to the best”—and that’s the right thing to do.

Conversely, when dialysis patients are seen to do better at home—long regarded as the best option in dialysis—we hear long and loud complaints about “selection bias” . This, inexplicably, turns the “offering the best to the best” argument back against home dialysis patients, almost as if going home is in some odd way “cheating”.

Opposite to its use in transplantation, somehow, selection bias seems used as a criticism of and not as praise for home dialysis: they only ‘do better’ because they are ‘selected to do better’ . Meanwhile, those professionals who offer and encourage home dialysis are accused of “cherry picking” the best patients out of facility care. Well, if I am a cherry picker, so be it...and may I keep finding more cherries to pick.

In an effort to resolve this issue, a brave but ultimately unsuccessful RCT, the 2nd trial arm (FHN2) of the Frequent Hemodialysis Network Study group, attempted to provide an answer (2). Unfortunately, all this ill-fated trial managed to do was to further muddy the waters. I was asked to summarize this view for the September 6th, 2014 issue of the ASN publication, Kidney News(3).In the final analysis, FHN2 was hopelessly underpowered (only 1/3 rd of the required number could be recruited), the recruiting rules had to be changed mid-trial, and the home trial arm did not comply with trial requirements …yet, even with 1/3rd of ‘N’, near significance was achieved in favor of home extended hour dialysis. But, as reporting rules dictate, near significance is not significant, and the trial reported no advantage to the home arm over conventional facility hemodialysis. Piffle!

And, in truth, who cares if either transplant or dialysis patients are “selected”? If they can do better, they should be allowed to do better! We should be encouraging patients, facilitating them—in any way we can—to achieve their maximum lifestyle, wellbeing and survival potentials.

We should be moving heaven and earth to create the systems, practices and supports that will allow as many as possible to break out of the cycle of dependence, suppression, and regimentation that facility-based dialysis enforces on so many patients who, if encouraged, facilitated, and supported, would manage and do better at home.

The next time I hear an accusation of “cherry picking” dialysis patients for home hemodialysis, I will picture the beauty of a cherry tree in blossom, I will marvel at the number of cherries it can produce, and I will ponder how to best manage to pick them, every one.

  1. Pauly RP, Gill JS, Rose CL et al. Survival among nocturnal home haemodialysis patients compared to kidney transplant recipients. Nephrol. Dial. Transpl. 2009; 24: 2915–19.

  2. Rocco MV, Lockridge RS, Beck GJ et al. The effect of frequent nocturnal home hemodialysis: the Frequent Hemodialysis Network Nocturnal Trial. Kidney International (2011) 80, 1080–1091.

  3. Agar J W M. Home Hemodialysis: Do We Need More Randomized Controlled Data? Kidney News. 6(9). September 2014.

Online version at: http://onlinedigeditions.com/article/Home_Hemodialysis%3A_Do_We_Need_More_Randomized_Controlled_Data%3F/1808063/224633/article.html

Comments

  • Margaret

    Oct 07, 2014 11:22 PM

    My husband is trying to make the decision re: PD/ HD. He is doing this without educating himself on either option. I am very frustrated with the whole process as I feel as though I am floundering in a sea of information. We went through an education program that lasted all of 30 minutes. We were sent home with reading material and DVD's to watch. I'm having a difficult time with this whole process, with the perio-hd how "married" to the process am I going to have to be as the "helper"? I have a feeling that I will be the care giver and my home will feel like a hospital. Help????????
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    • Dori

      Oct 08, 2014 2:16 AM

      Hi Margaret. I can't imagine how someone would make a choice without educating himself--except that he may be acting out of fear. Actually, that IS pretty common. You haven't said how he is doing physically or mentally. Does he think pretty well? Do his hands and eyes work? If so, he should be able to learn and do PD by himself, most likely. People who do PD don't need care partners--let alone "caregivers" (a term we don't care for and try not to use). People who do dialysis at home--PD or HD--tend to do better when they take responsibility and do as much as they can. This way, they also don't burden their partners. If your husband is impaired in some way and can't do the treatments by himself, then your role might be larger. Dr. Agar and Beth Witten and I built an online tool to help make the choice of a treatment more clear. It's called "My Life, My Dialysis Choice, and I would love to know what you think of it! You can try it at: http://www.mydialysischoice.org (paste that into your browser). Dr. Agar and I also wrote a book that goes with the decision aid, called "Help, I Need Dialysis!" People like you and your husband were exactly who we had in mind when we wrote it. It's available at http://www.lifeoptions.org/help_book, and explains ALL of the types of dialysis and their impact on your lifestyle. It sounds as if you are snowed under by too MUCH information right now. Please try the decision aid--it really should help.
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    • Fran

      Oct 08, 2014 12:54 AM

      Margaret, I remember six years ago feeling the same way. However today I realize the nightly PD treatment my husband opted for has been no issue for me. He is very careful to follow all the steps to be as sterile as possible, I do not do anything to help him each evening. He tracks, hooks up and disconnects by himself. I keep our bedroom clean and dust free. Our days are free for him to work, play or do what's ever he wants to do.
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      • John Agar

        Oct 08, 2014 4:30 AM

        Dear Margaret

        I have left a longer answer for you at our message board pages - the older but far, far more extensive Q&A resource we used till FaceBook kind of put a (sad) end to it.

        You can find it at

        http://forums.homedialysis.org/threads/3632-Margaret-is-fearful-of-her-husbands-dialysis-choices?p=23224#post23224

        I hope that link works for you ...
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      • Dori

        Oct 08, 2014 4:15 AM

        That's awesome, Fran, and it's great to hear that he is doing so well and staying active! Margaret, I forgot to mention that there is a book called "Arranging Your Life When Dialysis Comes Home" (you can find it on Amazon) that can help you figure out how to NOT have your home look like a hospital. It has some good tips.
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    • John Agar

      Oct 07, 2014 11:35 PM

      Margaret ... Sounds as if you need a bit more understanding of the basic differences and concepts of the various dialysis modalities. This blog page is probably not the best place to do this. Can you re-post your question (or, Dori - can you transfer her somehow) to the message board so I can tease this out for her there? And, Margaret, as I will be travelling over the next 3-4 weeks, my answers may be spaced by periods where/when I am out-of-contact, so, be patient.
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  • Sue Felton

    Oct 04, 2014 12:06 AM

    Just as PD isn't the best treatment for all dialysis patients, HHD or in center treatment isn't for others. We need to recognize the best treatment is the one which allows the patient the highest ability to have the life they want, and have the support system to achieve it.
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    • Dori

      Oct 06, 2014 12:02 AM

      Sue, Dr. Agar and I agree with you--that's why we worked with Beth Witten to develop "My Life, My Dialysis Choice," an interactive online tool that can help people match a dialysis option to their lifestyle and health values. You can see it at http://www.mydialsyischoice.org. That said, we also need to acknowledge that, lifestyle aside, some treatment options now really DO offer better outcomes than others. For years that wasn't really the case--PD and standard in-center HD are fairly alike (PD has better survival for most folks for the first couple of years, and offers a different quality of life profile). The nephrology community has been very slow to share the benefits of more frequent and/or longer HD treatments and still seems to treat all dialysis as if it is alike.
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      • Teresa

        Oct 07, 2014 8:09 PM

        Dori, my father is going back on dialysis this week 8 years post transplant. I have been so frustrated by just what you say. Most sources discuss how various options work and impact your lifestyle, but not outcomes. My father did CAPD 5 years pre-transplant. He was quite well-working and traveling- for 3 years, but then he became very sick. We are considering nocturnal HHD this time. Does nocturnal hemo 6x/wk have better outcomes than PD? How does 3x/week nocturnal compare with PD? (He is on medicare now and it sounds like getting more than 3 days coverage is hard). If he does PD again for a time, can he switch to NHD later? If the toxins have built up on PD will that negate the benefits of NHD? Truthfully, the thought of HD at all, and especially HHD, is unpleasant and scary to him-but the hope of feeling well longer than 3 years is very appealing. I have searched and called and searched some more and I'm having a hard time finding that information. Thank you!
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        • Dori

          Oct 08, 2014 2:28 AM

          Hi Teresa. I'm so sorry to hear that your dad's transplant is failing. Does nocturnal HD 6x/week have better outcomes than PD? In general, YES! Nocturnal HD 6x/week has better outcomes than any option but living donor transplant. It is about the same in terms of survival as a deceased donor transplant--about 3x better than standard in-center HD. PD is a bit better in terms of survival than standard in-center HD, but only while there is still some kidney function left (often 1-2 years, but this varies). Even 3x/week nocturnal HD is a better option for survival than PD. But, if he feels well on PD and would like to do that again for a while, PD is very gentle and easy to do, and he CAN change later. All of this information is in the "Help, I Need Dialysis!" book, and the decision aid.
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          • Teresa

            Oct 10, 2014 1:39 PM

            Thank you, Dori! You've been very helpful. The decision aid is great-especially the link to the research the information is based on.
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  • Dianne Kerr

    Oct 03, 2014 7:10 PM

    Thanks for your posting. I am a home hemodialysis patient and am on extended treatment.

    My doctor is an advocate of home hemodialysis and encourages those he believes will benefit by the treatment and who are compliant.

    I am grateful for this option and feel so much improved over in-center treatment.
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  • Carla hagood

    Oct 03, 2014 3:30 PM

    As simply as I can put this, there is not an overall one size fits all solution. Each patient is different and each treatment is different. Therefore depending on the person and what they need will determine which treatment is better for them. How do I know? I'm a dialysis patient.
    Let me give some examples. If a person is paralyzed, then home treatment may not be the best solution, in center may be, or if they have a dedicated caregiver PD might be the best solution for them. Take someone in my situation, somewhere between 45 and 50, active, alert, aware, educated on kidney failure and treatments. Home hemo is the best for me. I can log, control, and track everything going on with me and play an active role in my care plans and be part of the team, not just the subject the team works on. I get more treatments per week than in center and better clearance and feel 100% better. Someone who doesn't have the ability to keep track of logs and records would be better suited for in center.
    Transplants, not an option for me, why? Because I do not want to compromise my immune system any further than it is already compromised.
    Just my opinion.
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    • John Agar

      Oct 04, 2014 4:50 AM

      Clearly, home is not for all. But, it should be facilitated (made easier) for those who are capable, so that they can - if they want to - access home care.

      All dialysis patients (except where it is clear and obvious that there is no other option) should have all modalities - centre and home - considered, discussed and offered.

      Finally, the outcomes of home care should be made clear: the freedom to dialyse when it suits, the greater freedoms in fluids and diet that parallel increasing dialysis time and frequency, the options for dialysis through sleep - leaving the waking hours free from dialysis encroachment, the better well being, and the significantly greater likelihood of survival, and survival while feeling well.

      In addition - you are right - many are better suited to PD and the options between PD and HD in the home need to be discussed, on an individual basis, with each patient.

      Flexibility is also crucial, not only in mapping out different programs (and dialysis settings) for different patients as no two have identical needs, but also for individual patients, mixing and matching long and short runs to suit their timetables and their needs. I published in our own literature in ANZ on this very issue a decade ago in the journal of the Asia Pacific region --- 'Nephrology' --- Agar JWM et al. ‘Flexible’ or ‘lifestyle’ dialysis: Is this the way forward? Nephrology. 10(5): 525 -529, October 2005.

      I believe the principle of flexibility should be built into and encouraged in all programs, and all individual patient regimens. Sadly, in many countries, it is not.
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