By Allen R. Nissenson, MD, FACP

When continuous ambulatory peritoneal dialysis (CAPD) was introduced in the United States in 1979, there was great excitement amongst patients and providers. Here was a new form of treatment that patients could perform themselves at home, freeing them from the dialysis center, needle punctures and the restrictions of hemodialysis (HD). Very rapidly, nearly 17 percent of patients were using CAPD as a viable treatment option.

However, the hoped for medical benefits of CAPD, including tight blood pressure control, excellent control of blood sugar in diabetics, fewer hospitalizations and longer survival were not realized as more experience was gained, although these outcomes matched those of hemodialysis in most published series. On the other hand, the anticipated considerable lifestyle advantages of this form of home therapy were seen and even enhanced with the introduction of continuous cycling peritoneal dialysis (CCPD). It is of interest and concern, therefore, to see that in the United States and worldwide the number of patients choosing peritoneal dialysis (PD) has steadily declined in the past decade. What are the reasons for this and how can patients ensure that they have access to this important form of therapy, should they choose to use it?

First, could the waning popularity of PD be because of important differences in health outcomes of patients on this form of therapy compared to those on HD? The current available scientific evidence shows that clinical outcomes of patients on PD are equivalent to those on HD, as long as "adequate" toxins are removed by either treatment (that is, adequate dialysis is performed).1

Second, is the use of PD decreasing because physicians and patients think this is a poor form of therapy? We studied this issue a number of years ago using survey methodology, examining physician preferences in California, North Carolina and in Australia/New Zealand.2 Clinical patient examples were used to determine preferred ESRD modalities from the physician's perspective.

The modality choices included living related donor transplantation, cadaver transplantation, home PD, home HD and facility HD. There were three categories of patients - those with diabetes, patients over 60 years old and patients in general. There was amazing consistency in matching patients with preferred modalities in all three regions surveyed, as well as a marked disparity between what physicians stated was the best modality for a given patient and what modality was actually used for similar patients in the particular area. The reasons that doctors did not use what they said was best for patients were unclear but one important conclusion is that patients and physicians must together reach a decision about a dialysis modality and when this is done, it is likely that a greater and more appropriate use of PD would result.

Although the patient/physician teamwork is critically important to the appropriate use of PD, the results of two other large international studies shed additional light on how this treatment choice decision is made.3,4 Data for these studies were obtained from a group of U.S. nephrologists who had active PD programs, from physicians outside the U.S. who were at universities and/or in clinical practice and those doing clinical research into PD. Information was obtained from Canada, Hong Kong, the United Kingdom, Japan, Italy, France, Brazil, Australia and the United States, among other countries/regions.

In these studies, it was clear that the payment to the doctors and/or dialysis facilities, as well as the availability of resources including outpatient dialysis stations and nursing staff, were key factors in the selection of PD vs. HD. Where reimbursement and resource availability favor one form of dialysis over the other, the use of that form of dialysis is much greater. Where reimbursement and resource availability do not favor one form of dialysis over another, other factors are critically important including physician, nurse and patient familiarity as well as the level of knowledge/comfort, social mores and cultural habits.

What does all this mean to dialysis modality selection in the United States ? It must be kept in mind that no matter what treatment of dialysis patients and physicians feel is best medically, the decision is then run through a prism of reality. In the United States , the following have a significant impact on the modality that is chosen, which is increasingly HD rather than PD:

There is an abundance of outpatient HD facilities. The high fixed costs of these facilities must be distributed over as large a patient base as possible, creating an incentive for facilities to keep patients in-center.

Dialysis facilities must often depend on income from ancillary services, in particular injectable drugs (EPO, iron, Vitamin D), to survive because of the poor reimbursement for dialysis services. PD patients use fewer of these ancillary services and are thus a lost source of revenue in this regard. 

PD is now suffering from a "vicious cycle" syndrome. That is, PD use has been declining; with fewer patients, nephrology trainees are not trained adequately in PD and are not comfortable with it when going into practice; with fewer knowledgeable physicians, there are fewer patients recommended for PD; PD programs shrink and training nurses move on; the result is a loss of interest in PD and the infrastructure necessary to develop and sustain quality programs.

What patients and physicians should insist on is that the most appropriate modality of dialysis, PD or HD, be provided when it will result in the best health outcomes for each individual. How can this be accomplished?

Some physicians still do not believe that PD leads to the same health outcomes as HD. One way to address this is through a large clinical research study in which patients are assigned to HD or PD and followed over an extended period of time. This is logistically difficult and very time consuming. Another approach would be to do a scholarly review of the available medical literature and to perform an appropriateness analysis.5 This effort could stress the integration of various modalities, clearly describing how they are complementary, not competing. If published in a respected medical journal, such a study would be difficult to ignore.

The centralization of PD training centers should be considered to address the crumbling base of PD programs. Such centers would not need to provide ongoing care once patients were trained, so patients would return to their own doctors after training was completed. This approach would be of particular value considering the severe nursing shortage in dialysis today.

Because of the shortage of trained nurses, the development of a pool of experienced training and/or ongoing management nurses would be of great value to nephrologists considering the implementation of a PD program but hesitating because of concern over nurse availability.

Targeted efforts to increase the exposure and training of nephrology trainees in PD should be explored. Nephrology training directors are required to provide PD experience for their trainees and would likely be eager to work to develop more robust training experiences.

Patients must insist that their caregivers inform and educate them about PD and HD, the advantages and disadvantages, so that they are true partners with their care team in arriving at a decision regarding dialysis treatment. Remember, the key is to select the appropriate treatment, to meet your needs, for your particular medical circumstances, at the appropriate time in the course of your illness. As clinicians, scientists and patient advocates, nephrologists must also step up and lead this effort, working with patients to drive the changes in the current delivery system which will lead to the best patient outcomes achievable with our current technology.

References:

Murphy SW, et al. Comparative mortality of hemodialysis and peritoneal dialysis in Canada . Kidney Int 57:1720-1726, 2000.

Mattern WD, McGaghie WC, Rigby RJ, Nissenson AR, Dunham CB, Khayrallah MA. Selection of ESRD treatment: an international study. Am J Kidney Dis 13:457-464, 1989.

NissensonAR, et al. Non-medical factors that impact on ESRD modality selection. Kidney Int 43:S120-S127, 1993.

NissensonAR, et al. ESRD modality selection into the 21st century: the importance of non-medical factors. ASAIO J 43:143-150, 1997.

Shekelle PG. Are appropriateness criteria ready for use in clinical practice? N Engl J Med 344:  677-678, 2001.

This article was modified with permission from "What Other Factors Influence Modality Choice?" written by Dr. Nissenson and originally published in the March 2002 issue of Nephrology News & Issues.

Dr. Nissenson is Professor of Medicine and Director of the Dialysis Program at the UCLA School of Medicine.

This article originally appeared in the November 2002 issue of aakpRENALIFE Vol. 18, No. 3.

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