Peritoneal Dialysis Use

Jain et al. conducted a comprehensive review of PD use between 1997 and 2008 by contacting a representative from the national dialysis registries for each country. PD use was reported as number of patients on PD, PD incidence, PD prevalence per million population, and PD prevalence as a percentage of dialysis patients. Focusing on the latter statistic, countries can be classified into high use (50% of greater), moderate use (10% to 50% use) and low use (less than 10%) ( Table 30.1 ).

This study, although comprehensive in its methods, does not reflect the most recent PD use statistics, and some countries have implemented policies to increase PD use since 2008. For example, in the United States, the Center for Medicare and Medicaid Services (CMS) implemented an expanded prospective payment system that bundled most of the services provided to dialysis patients starting January 1, 2011 to promote PD use. Prevalent PD use, according to the US Renal Data System (USRDS) renal report, has increased from 7.2% to 9.8% from 2010 to 2014.

In Thailand a PD-first policy was implemented in 2008 that dramatically increased prevalent PD use from 9.5% in 2008 to 30.0% in 2014, according to the Thailand Renal Replacement 2014 report. In Ontario, Canada, the Ministry of Health and Long-Term Care began actively promoting PD in 2005. The policy was followed by the formation of a renal agency called the Ontario Renal Network in 2011, which has a strategic goal to increase home dialysis. Prevalent PD use has grown modestly from 18% in 2005 to 19.4% in 2015.

Framework for Understanding Peritoneal Dialysis Use

The use of PD can be explained by a variety of frameworks. For example, Liu et al. identifies the importance of government policies, economic factors, and provider and patient education. Other explanations focus on system, provider, and patient factors. Our preferred framework is to focus on the process of care that requires patients to pass through six steps to successfully start PD therapy. At each step, the impact of policies, education, and provider and patient factors can be considered.

Identification of Potential Peritoneal Dialysis Patients

PD use will be increased in programs that have a robust intake and accounting process to identify all potential PD candidates. The majority of patients are followed in predialysis clinics by nephrologists or interdisciplinary teams. The receipt of predialysis care is strongly associated with PD use. For example, a predialysis education program implemented by Fresenius Medical Care in the United States was associated with an adjusted odds ratio (OR) of 5.13 (95% confidence interval [CI], 3.58 to 7.35) for selecting PD.

In our quality improvement system (DMAR system) we have found that interdisciplinary meetings conducted every 2 weeks to identify and review all new patients starting dialysis can greatly improve the identification of potential PD patients. These meetings are particularly important for patients who start dialysis acutely in the hospital. Hughes et al. found that 46% of the patients starting dialysis in Canada began as an inpatient, despite 62% having received at least 4 months of predialysis care.

Patients starting dialysis urgently in the hospital are normally treated with hemodialysis using a central venous catheter. The advent of urgent start PD programs, usually defined as PD catheter use within 2 weeks of insertion, allows these patients to consider PD as their initial dialysis modality rather than receive hemodialysis (HD) as a default. Urgent-start PD studies indicate that this strategy can be successful, with acceptable rates of complications, although catheter dysfunction was increased in some studies because patients were acutely ill and could not undergo the same level of preparation before PD catheter insertion as those with elective PD starts. The impact on PD use is less clear, but urgent-start PD should increase PD incidence use by offering acute patients the option to start on PD rather than hemodialysis. Studies are generally small, with sample sizes of fewer than 100 patients, and some patients used their catheter for PD within 48 hours of insertion.

Identification of PD candidates among patients starting dialysis acutely may also be facilitated by use of nurse navigators. Rioux et al., in a study from Toronto, Canada, found that 21.5% of patients starting dialysis urgently without prior modality education chose PD when targeted by an advanced nephrology practice nurse. Similarly, use of a nurse navigator for urgent starts was found to increase the likelihood of transitioning from in-center hemodialysis to independent forms of dialysis (OR 3.75; 95% CI, 1.08 to 13.05) in a single-center study from Vancouver, Canada.

Assessment of Peritoneal Dialysis Eligibility

All end-stage renal disease (ESRD) patients who are likely to initiate or have initiated chronic dialysis therapy should be assessed for PD eligibility. The average rate of eligibility among multiple dialysis programs in Ontario was 65%, although experienced programs have considered up to 80% of their patients eligible for PD. Eligibility is generally determined by either a nephrologist or interdisciplinary team based on the presence of contraindications to PD, barriers to self-care PD, and the availability of support.

Contraindications to PD are not completely objective, and providers in programs may have different levels of comfort treating patients with different medical conditions ( Fig. 30.1 ). Some programs may also use extended PD catheters or presternal PD catheters, which allow patients with a large pannus or a colostomy/ileostomy to receive peritoneal dialysis. Some programs may also have access to surgeons who can perform PD catheter insertion using advanced techniques such as adhesiolysis and hernia repair, which expands eligibility for PD. With these considerations in mind, our prospective study found that 22% of patients were considered by their nephrology team to have a contraindication to PD.

Contraindications to peritoneal dialysis (PD).

Studies also indicate physical, cognitive, and social barriers to self-care PD are common. Our prospective study found that 53% of patients assessed for PD (excluding those with contraindications) had at least one physical barrier to PD, such as decreased strength, dexterity, vision or hearing. At least one cognitive barrier to PD was present in up to 15% of patients and included language barriers, dementia, a history of nonadherence, and active psychiatric conditions. When PD patients are screened for cognitive dysfunction using a battery of validated tests, up to 45% of PD patients have evidence of cognitive decline. Social barriers may be present when patients are primary caregivers for others (children or elderly parents), have employment issues, or live in residences such as small apartments or retirement homes that make PD more difficult. Although these physical, cognitive, and social barriers are common in PD patients, it is not known if they explain variance in PD use among programs within or between countries.

In contrast, the availability of support likely influences PD use at the program or regional level. We previously reported that the availability of home care support for PD increased eligibility from 65% to 80% in an elderly dialysis population in a single-center study. In France, assisted PD was chosen by 1232 out of 1613 (76%) of PD patients older than 75 years. We also reported that the availability of family support increased PD eligibility from 18% to 46% depending on the presence of barriers to self-care PD. The availability of home care assistance varies from country to country, but this model of PD delivery has been reported in studies from Canada, United Kingdom, France, Denmark, Switzerland, Spain, Brazil, Taiwan, and China.

Offer and Choice

Once a patient is deemed potentially eligible for PD, he or she is provided modality education. Modality education takes many forms and can be provided by physicians, nurses, or specialized educators. The format of educational programs can include one-to-one sessions, group education, printed materials, videos, or websites. Patients may also now access material directly from the Internet or benefit from peer-to-peer education. Given these many options, it is not surprising that education varies widely among dialysis programs. Regardless of the format of modality education, it is necessary to increase PD use. For example, Mehrotra et al. reported that only 34% of patients in the ESRD Network 18 reported being offered any form of PD when they started renal replacement therapy. This may partly explain the low penetration of PD in the United States because receipt of education is consistently associated with choosing PD. A recent review of educational studies we conducted found that modality education increased PD choice by a factor of 4.6 in a randomized study and a factor of 2.2 in prospective observational studies. Decision aids for patients, such as the Yorkshire Dialysis Decision Aid, “My Kidneys, My Choice Decision Aid”, and “My Life, My Dialysis Choice” may also allow patients to make better choices. A prospective study by Winterbottom et al. found their Yorkshire dialysis decision aid was associated with higher information scores, higher decision clarity and feelings of control, and higher levels of shared decision making among patients’ families. These are all positive results, but they did not evaluate the impact on actual home dialysis use.

Patient choice, or whether patients are given a choice at all, is a relatively easy factor to modify and likely explains much of variance in PD among programs. In prospective studies, approximately 50% of patients chose PD when they were offered it in a systematic fashion. However, the choice rate will vary widely from program to program depending on their philosophy. Some programs employ a neutral approach where patients are provided fact-based education with little promotion, similar to consent for a clinical trial. For example, France has a legal requirement to offer patients modality choice. However, most programs likely encourage patients to consider home-based therapies and actively promote them by strongly emphasizing the benefits of home dialysis. Other countries, like Hong Kong, Thailand, and Mexico, employ PD-first policies where choice is explicitly restricted. Other countries such as New Zealand may not explicitly restrict choice but make it challenging for some patients to receive in-center hemodialysis, resulting in high home dialysis rates.

PD-first policies may conflict with the patient-centered care and the principle of shared decision making. Shared decision making is defined as “an approach where clinicians and patients share the best available evidence when faced with the task of making decisions, and where patients are supported to consider options, to achieve informed preferences”. Other research suggests shared decision models, when employed thoughtfully, can increase home dialysis without restricting patient choice.

It is important to note that expressed choice before the initiation of dialysis does not always translate into actual receipt of PD therapy. For example, Leibmen et al. found of 124 patients who chose PD at the time of education, 59 started dialysis therapy with PD, and 65 started with HD. On day 91 of dialysis therapy, a total of 60 patients were on PD therapy and 55 were on HD therapy. Proponents of buried PD catheters have argued this technique can “lock in” patient choice and is one of the advantages of placing buried PD catheters at higher levels of GFR. Buried catheters are inserted so the external limb of the catheter is buried under the skin, permitting healing and tissue ingrowth of the cuffs in a sterile environment. Buried catheters cannot be flushed and must be externalized before use.

The availability of support can also increase PD choice. Family or home care support was associated with increased likelihood of choosing PD, and the impact of support was more pronounced in patients with barriers to self-care.

Insertion of the Peritoneal Dialysis Catheter

Patients who chose PD must undergo PD catheter insertion to receive PD. PD catheter insertion among eligible patients is an objective measure of choice and can be used to compare choice rates among programs in epidemiological studies. Methods of insertion include percutaneous techniques, generally performed by nephrologists and radiologists, and surgical techniques, including laparoscopic and open insertion, performed by surgeons. Randomized trials have not consistently found significant differences in complication rates between the different methods, and the most recent guidelines of the International Society for Peritoneal Dialysis (ISPD) recommend using local expertise and availability to guide the method of insertion. Some advocates of laparoscopic placement with advanced techniques report outstanding results with very low complications rates, but it is not known whether these results are generalizable to all programs.

A study we conducted in Ontario, Canada found patients who had PD catheters inserted by nephrologists were more likely to receive at least 4 weeks of PD use. However, it was not known if this result was due to be better timing of insertion, patient selection, or reduce complication rates. Higher-risk patients with previous abdominal surgeries and scarring may be selected for surgical placement of PD catheters. In this study, 17% of PD catheters did not provide at least 4 weeks of PD therapy during follow-up, but the reasons could not be determined from the administrative data. Asif et al. reported an increase in the prevalent use of PD at three centers from 16% to 18% to 22% to 32% when nephrologist-based insertion of PD catheters was introduced.

In summary, methods of insertion vary widely and it is not clear the impact the method of insertion has on PD use. Laparoscopic insertion with advanced techniques could provide superior technical results, but its impact on use is unknown. In contrast, nephrologist-based insertion may also improve use, but the mechanism is not known. Regardless of technique, high rates of insertion-related complications, particularly ones causing early technique failure, will negatively affect PD use.

Receipt of Peritoneal Dialysis

Once the catheter is in place, PD can be initiated. ISPD guidelines recommend at least 2 weeks of healing before using PD catheter. However, urgent-start PD programs have used PD catheters 24 to 48 hours after insertion. In contrast, buried catheter studies are often exteriorized months or years after initial placement ( Table 30.2 ).

Outcomes of Peritoneal Dialysis Therapy

Kidney transplantation is felt to provide the best patient outcomes and quality of life and is the most cost-effective form of renal replacement therapy available in settings that have the necessary health system infrastructure to support transplant programs. However, donor organs are a scarce resource and not all patients are eligible for a transplant. As a consequence, the vast majority will receive dialysis as the first form of treatment for end-stage kidney failure.

In an ideal world, information about patient outcomes from several, well-designed randomized controlled trials comparing different dialysis treatments would be available to guide shared decision making and help patients and providers choose between the different options. Unfortunately, attempts at randomized comparisons have been unsuccessful. Although there are numerous potential comparators (e.g., transplantation, home hemodialysis, or conservative management), we focus our discussion on studies that have compared the outcomes of patients treated with PD and HD.

Attempts at Randomized Comparisons of Peritoneal Dialysis and Hemodialysis

Investigators in the Netherlands attempted to conduct a randomized trial of incident dialysis patients at 38 participating sites. Although 63% of screened patients were deemed eligible for the trial, only 38 of 773 eligible patients consented to participate and it was stopped because of poor accrual. This study was nonetheless informative because it demonstrated the fact that patients appeared to form strong preferences for one modality or another when educated about their treatment options and were unwilling to subject themselves to randomization. This is an important consideration, particularly in environments where PD-first policies are being contemplated.

A subsequent feasibility study was conducted in China to determine whether patients would be willing to be randomly assigned to either PD or HD ( clinicaltrials.gov NCT00510549 ). The investigators had planned to enroll 50 patients to determine whether a larger trial looking at the impact of treatment modality on mortality, morbidity, quality of life, and cost effectiveness was feasible. According to clinicaltrials.gov , recruitment was completed in August 2008 and a protocol for the larger trial was registered in 2011 ( clinicaltrials.gov NCT01413074 ). Recruitment was terminated in 2013 after 416 patients were enrolled, and final data collection for the primary outcome measure was to be completed in December of that year. The results of the pilot and larger trial have not been published to our knowledge.

In the absence of data from randomized controlled trials, we must rely on outcomes of observational studies. Although there is a general feeling among experts that the outcomes of patients treated with PD and HD are equivalent, much of the existing literature is based on registry studies with unclear data quality, which have included patients who might not be eligible for both therapies and patients who are acutely ill, have a poor prognosis, and are treated almost exclusively with HD. These and other issues may introduce bias into nonrandomized comparisons. Given that many jurisdictions are actively promoting PD and some have implemented PD-first policies, it is important to be aware of the methodological challenges inherent in such comparisons and the level of confidence we should have in prior comparative studies.

Data Validity

It is important that data regarding baseline patient characteristics, changes in treatment modality, and patient-level outcomes are valid to ensure a fair and unbiased comparison of PD and HD. If differential reporting of patient characteristics or outcomes occurs, this can lead to systematic bias. Ideally, data collected as part of a well-designed prospective cohort study or data from a validated source would be used for PD versus HD comparisons. However, the majority of studies comparing outcomes in individuals treated with PD and HD have been based on data from regional or national dialysis registries, particularly in recent years.

Registries can be an important source of information and are often used for comparative studies of PD and HD. It is generally assumed that data from dialysis registries are valid, but very little work has been done in this area to confirm the validity of the data sets and the available information raises some important concerns. Longenecker et al. compared comorbidity information collected using Form 2728 (Medical Evidence Report for end-stage renal disease in the US Renal Data System Registry) to data from the prospective Choice for Healthy Outcomes in Caring for ESRD (CHOICE) study. The authors found that comorbidities were “significantly underreported on Form 2728” and found that performance of the registry data were systematically different among those treated with PD compared with HD. In fact, they cautioned, “bias may be introduced if Form 2728 data are used to study associations between comorbid conditions, treatment, and mortality or other outcomes.” Subsequent studies examining the validity of Form 2728 for identifying glomerular diseases have shown poor agreement with kidney biopsy results.

Validation studies of other national registries, such as the Canadian Organ Replacement Register and the Australia and New Zealand Dialysis and Transplant Registry (ANZDATA), have been conducted. Moist et al. found that there was underreporting of comorbidities in CORR, similar to the USRDS. However, when hazard ratios were calculated for individual comorbidities using CORR data and compared with those obtained using information taken from chart review, there was good agreement between the two sources. Although this is somewhat reassuring, the authors didn’t specifically look to see if there were systematic differences between the coding of comorbidities in PD and HD patients or determine the validity of other important variables required to conduct an unbiased comparison of these two modalities (e.g., changes in treatment status or the occurrence of important patient outcomes). Similar findings were reported in a retrospective audit of 175 HD patients registered in the ANZDATA registry. Gray et al. found that primary renal disease was correct in 86% of cases; date of first dialysis was correct in 94% of cases, but there was significant underreporting of most comorbidities (low sensitivity and relatively high specificity). No information was available for PD patients or for important patient outcomes.

Valid data are necessary foundation for robust, unbiased comparisons of PD to HD. However, several other methodological considerations can influence the observed results. It follows that it is important to ensure that studies are well designed, in an attempt to minimize bias and avoid misleading results and conclusions. These issues will be explored further in the context of the relevant outcomes discussed next.

Comparing the Outcomes of Patients Treated With Peritoneal Dialysis and Hemodialysis: Survival

Studies examining the impact of dialysis treatment modality on patient survival have been inconclusive, but most experts believe that PD and HD are associated with similar survival. Some studies have found a benefit with PD, whereas others have reported a survival advantage of HD or little or no difference between modalities.