Peritoneal dialysis in 2011: Challenges, opportunities, and new insights

The year 2011 has the potential to be a landmark year in the history of peritoneal dialysis (PD) in the United States due to bundling of payment for end-stage renal disease (ESRD) services. According to the new bundled payment structure, PD will be more profitable to the dialysis unit owners due to a lesser need of erythropoetin and intravenous iron, and use of cheaper oral vitamin D analogs in place of more expensive injectable vitamin D preparations. Moreover, there has been higher reimbursement for ESRD services during the first four months if a patient is started on any home dialysis modality, which went into effect January 2011. The editors of Dialysis & Transplantation have chosen to dedicate this entire issue to the modality. I am indeed honored to have the privilege of editing this special issue, and am indebted to my mentor, Dimitrios G. Oreopoulos, MD, PhD, with the University of Toronto, who taught me the science of PD and helped plan this issue. We are fortunate and delighted to present contributions from people who are major players in the PD literature, and I thank them all.

This issue focuses on growing a PD program. Growing a PD program involves enrolling more patients, and retaining them. We did not have look far to find Ramesh Saxena, MD, PhD, with the University of Texas Southwestern Medical Center in Dallas who shares his experience of expanding a PD program at a time of a dwindling population of PD patients elsewhere.1 His article clearly stresses the effectiveness of assembling a dedicated multidisciplinary team on modality education for all of his CKD stages 4 and 5 patients. He discusses a model that works and is worth reproducing at least in similar settings.

Historically, the dialysis industry has funded landmark studies in PD research.2, 3 James Sloand, MD, from Baxter gives a brief industry/nephrologist perspective to the effects, opportunities, and challenges the bundling of ESRD services offers to the growth of PD in the U.S.4 We hope his optimism becomes a reality. While bundling may help by encouraging the owners of dialysis units to provide the infrastructure, it will not address the mindset of the patient who is not keen on self-care for different reasons nor will it address a nephrologist's reluctance to offer a treatment that he or she has not offered for many years—or in his or her entire career—or has never learned about during fellowship training. Beneficiaries of the new payment structure under bundling are owners of dialysis units, insurance companies, including Medicare, Medicaid, and private insurance companies. The hope is that this benefit will trickle down to appropriate use of treatments beneficial to patients. Will this mean a growth in the number of PD patients in the U.S.? Only time will answer that question.

One potential disadvantage of bundling is that it may stop innovation in the development of new PD solutions, the treatment of anemia, and the treatment of renal osteodystrophy in the U.S. because the cost of any solution or drug will have to absorbed by dialysis unit owners. Another potential disadvantage is that it is likely owners of dialysis units may limit the choice of drugs for the treatment of anemia and renal osteodystrophy. A physician's ability to prescribe the newer and more expensive vitamin D analogs may become limited by the need to justify their choice. So far the ‘soft’ evidence to favor newer vitamin D analogs was sufficient to favor the use of newer generation medicines. Now, this evidence is being considered insufficient to justify the added cost. It is likely that, when phosphate binders are included in the bundle in future, use of cheaper calcium-containing binders will go up to reduce the use of more expensive non-calcium containing binders. On the other hand, this handicap might stimulate more research in the development of other medications and interventions to improve the dismal survival of patients with ESRD. The ESRD population is begging for any such breakthrough to improve the survival of this group of very sick patients.

An equally important issue in growing PD as a modality is retaining patients on the therapy once it is initiated. The appropriate use of a peritoneal equilibration test to plan a dialysis regimen to deliver adequate dialysis and to tailor therapy according to a patient's peritoneal membrane characteristics is important. Diagnosing treatable causes of ultrafiltration failure is important to retain some of these patients on PD. Maintaining residual renal function (RRF) is paramount to the success of PD in the long run. In this issue, Simon Curran, MB, BCh, BAO, PhD, and Joanne Bargman, MD, FRCPC from the University of Toronto review the importance of RRF and review the measures necessary to maintain RRF over time.5 Dr. Bargman's 2001 paper reanalyzing the CANUSA study and stressing the importance of RRF is noteworthy here.6 Something relevant to additionally note here is that in young patients with longer remaining lifespans, placing PD, transplantation, and hemodialysis in the correct order might allow us to take advantage of RRF to complement PD and thereby lengthen the survival once ESRD begins, especially in large-sized patients.

Addressing the biocompatibility of dialysis solutions in increasing the longevity of the peritoneal membrane is another important topic. We are fortunate to have Jose Diaz-Buxo, MD, from Fresenius Medical Care address this topic.7 Icodextrin-based dialysate is available in the U.S. market and has the potential to increase ultrafiltration and, hence, has the potential to allow continuing PD in patients with more permeable peritoneal membrane who may otherwise have needed to switch to hemodialysis. The biggest practical barrier to the use of icodextrin is its cost. Dr. Diaz-Buxo has brought to our attention that there is another potentially more biocompatible neutral pH peritoneal solution approved by FDA but not yet commercially available in the U.S. It is to be seen if the industry will be able to make it available to patients in this “capitated” environment of bundled reimbursement for dialysis in the U.S. It will also depend on whether expensive PD with these biocompatible solutions will still be more profitable than hemodialysis to the owners of dialysis units. If it indeed makes PD last longer it may still be profitable to certain dialysis owners who also are dialysis product manufacturers.

In my review paper in this issue, I discuss some logistics of managing obese patients undergoing PD.8 While it is obvious that big patients need more dialysis, it is interesting to note that since fat has less water than muscle and since urea nitrogen is freely distributed in water, it is not that difficult to provide adequate solute clearance adjusted for total body water.9 There is a theoretical argument that heavier patients may need lesser Kt/V based on anthropological comparison of normal GFR in animals of different weights. I have also shared some of our unpublished data on obese PD patients related to their quality of life. Some creativity on the part of surgeons to reduce the exit-site infections is necessary.

We are fortunate to have a contribution from a pioneer in the field of infections. Beth Piraino, MD, from the University of Pittsburgh has authored a review on the important issue of preventing peritonitis.10 It is timely that the International Society of Peritoneal Dialysis (ISPD) position paper on the prevention of peritonitis will be published soon.11 In her paper in this issue of D&T, Dr. Piraino suggests that each unit should track the peritonitis rate in quality-assurance meetings and that peritonitis rates should be reported in a uniform manner. I hope the ISPD position paper stresses this suggestion. It is important to identify rates of preventable peritonitis caused by coagulase-negative Staphylococci, S. aureus, and Pseudomonas peritonitis and track them to implement the appropriate preventive strategies. The main preventive measures include prevention and timely treatment of wet contamination by proper training of the patients and the training nurses, retraining of the patients and training nurses soon after an episode of a preventable peritonitis, the use of gentamicin cream to the exit site, prophylactic use of antibiotics and draining the dialysate prior to colonoscopy, and use of antibiotics prior to a dental procedure. The wide use of exchange devices may be beneficial. We have recently had an episode of peritonitis due to patient disconnecting the tubing to remove the fibrin with a toothpick! In addition, I encourage you to read our experience of five-fold reduction of peritonitis by taking all these measures, reducing the proportion of culture-negative peritonitis by injecting the peritoneal effluent into the blood culture bottles at the clinic before the effluent is sent for culture, and having separate quality-assurance meetings that specifically address reducing peritonitis rates.12

The areas not covered in this issue that we hope to address in the near future are the science of hernia management, assisted peritoneal dialysis, encapsulating peritoneal sclerosis and opportunities to improve PD education among nurses and physicians. Appropriate management of hernias with skilled surgeons would reduce recurrence rate of hernias in PD. PD assisted by a helper would potentially increase new patient enrollment, and offering PD in nursing homes could potentially lessen the inconvenience of dialysis for elderly people and also save healthcare dollars. PD education is a huge issue and it is important to promote this to retain the skill of an already-small pool of nurses and doctors with the required skill level to manage patients on PD and to engage new healthcare workers to grow PD and get involved in PD research.