Dialysis & Transplantation最新文献

On radionuclide scanning, acute tubular necrosis (ATN) commonly manifests as adequate perfusion represented by persistently diffuse radiotracer activity throughout the parenchyma of renal allograft transplanted with a single artery with no or poor excretion of radiotracer. Following transplantation, the abnormal “wedge-shaped” finding of radiotracer retention in an isolated arterial segment of the graft kidney on Tc-99 m mercaptoacetyltriglycine (MAG3) scan with significant clearance on sequential study demonstrates vascular etiology of tubular dysfunction and represents segmental ATN rather urinary extravasation or artifact. Dial. Transplant. © 2011 Wiley Periodicals, Inc.

Peritoneal dialysis (PD) solutions have evolved since Boen described the appropriate composition of a suitable fluid comprising an osmotic agent, electrolytes, and buffer substance in 1969. New solutions introducing alternative osmotic agents and bicarbonate as an alternative to lactate-buffered solutions have been developed. These so-called biocompatible solutions belong to a very heterogeneous group of PD fluids that share some features but are distinct in other aspects. All biocompatible solutions have a substantially reduced level of toxic glucose degradation products (GDPs). However, the new solutions differ in their absolute GDP content, osmotic agent, buffer substance, and pH. The differences from the conventional solutions and the characteristics of the distinct new solutions are presented in this review together with a discussion of their potential clinical benefits and implications. Dial. Transplant. © 2011 Wiley Periodicals, Inc.

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 solution

Dramatic changes in the end-stage renal disease (ESRD) prospective payment system (PPS) were enacted in 2011. Among the multiple changes brought about by the bundling of ESRD services, modifications were made explicitly “to encourage the use of home peritoneal dialysis (PD) among dialysis patients where feasible.”1 Peritoneal dialysis generally utilizes fewer overall healthcare resources, a fact that should have a favorable impact for dialysis facilities in the fixed payment environment of bundled ESRD services. It is anticipated that facilities will encourage PD and make it more accessible to nephrologists and their patients. But is PD always a viable option for patients who both want and are suitable for it? What factors should be evaluated in determining feasibility?

The incentive provided to facilities by the new PPS should afford nephrologists, and the patients they care for, the opportunities for an equally effective, less costly, and in some instances, a safer form of renal replacement therapy (RRT). It should enhance the likelihood of an additional option being offered to many individuals with ESRD as they decide how dialysis will impact their lifestyle. But a number of challenges need to be addressed, given the limited clinical use of PD in the past 15 years.

The use of peritoneal dialysis in the United States peaked at 16% in 1985, remained at a plateau of 14-15% through 1993,2 and has steadily eroded to a current 8% of Americans receiving dialysis today.3 With 92% of dialysis patients receiving hemodialysis (HD), the latter is the RRT “default.” There are many reasons for the decline of PD, but the lack of infrastructure and clinical support in current dialysis facilities certainly compromised the capacity to deliver full, quality care.2, 4 Nephrologists and patients must make the life-sustaining, clinical “choice” of therapies based on tangible, current services and expertise. When there is great disparity in support and expertise, there really isn't much of a choice.

To do something well, we must do it often. The knowledge and skill necessary to develop expertise requires frequency and focus. Logically, it would seem that PD outcomes would have suffered as the proportion of dialysis patients using this therapy declined. However, this was not the case. Fully adjusted patient and technique survival outcomes have improved.2, 5 This may be attributed to the centralization of expertise in larger centers,2-4, 6 but results could undoubtedly be replicated elsewhere if sufficient resources and focus are provided.

Should dialysis facilities adopt measures to support PD, nephrologists may modify prescriptive RRT guidance in a way that could improve the outcomes for a significant number of their patients. Currently four of every five patients starting HD do so with a central venous cathete

It is widely assumed1 that obese or large-framed patients on peritoneal dialysis (PD) will have difficulty achieving solute clearance targets considered adequate by National Kidney Foundation (NKF)-KDOQI guidelines,2 especially in the absence of residual renal function. A U.S. national survey has shown that U.S. nephrologists are 2.3 times more likely to recommend PD to patients with body weight less than 200 lb than to those weighing more than 200 lb.3

This perceived difficulty arises from the larger total body water (TBW) volume and body surface area (BSA) present in larger patients, which are used to normalize weekly urea (Kt/V) and weekly creatinine clearances (WCC), respectively. Larger TBW and BSA obligate larger and sometimes unobtainable drain volumes to achieve targeted clearances. Mathematical models predict that patients over 80 kg cannot receive adequate dialysis with even four 3-L continuous ambulatory peritoneal dialysis (CAPD) exchanges daily.4, 5 A multicenter study reported a Kt/V >1.7/wk in 54.2% and a WCC >54.4 L/1.73 m²/wk in 70.8% of patients heavier than 100 kg.6 We have reported success rates in reaching the higher solute clearance targets recommended by NKF-KDOQI for large or obese patients.7 Since 2006 KDOQI guidelines suggest lower Kt/V targets (of 1.7/wk) than the initial KDOQI guidelines and since WCC is not taken into consideration, a higher proportion of patients is expected to achieve the current targets.8

There are other potential barriers to successful PD outcomes in obese patients. The larger exchange volumes and frequency and/or the long time required on the cycler for large patients to receive adequate dialysis may significantly impair quality of life, including the ability to work or engage in recreational activities. Finally, obese patients, who may not be able to directly visualize the exit site due to their protruding abdomen, may have difficulty taking proper care of their catheters. This may result in an increased risk of exit-site infection or peritonitis. Piraino et al. showed that patients weighing more than 110% of ideal body weight have similar peritonitis and exit-site infection rates but a greater risk of catheter loss due to infection.9

The increased emphasis in recent years on providing adequate solute clearance to PD patients has led many nephrologists to conclude that obese patients may be too “big” to reach PD adequacy targets, especially after the loss of residual renal function. A national survey on U.S. nephrologists' recommendation of dialysis modality clearly showed that only 28% of patients with weight over 200 lb were recommended for PD compared with 44% of patients with weight less than 200 lb (adjusted odds ratio 0.44, 95% CI 0.35-0.55).3

Nolph et al.4 calculated that patients with standard weights mo

The population of the United States is experiencing rapid growth of end-stage renal disease (ESRD) requiring renal replacement therapy (RRT). There were more than 548,000 ESRD patients in 2008, consuming 7% of the Medicare budget and $39.5 billion in total costs. With an annual growth of 6%, the ESRD population is projected to grow to more than 775,000 dialysis patients in 2020.1 RRT options include hemodialysis (HD), peritoneal dialysis (PD), and renal transplant. While renal transplant remains the RRT of choice, the proportion of ESRD patients receiving renal transplant has not changed in the past decade. With the increasing numbers of ESRD patients requiring dialysis, one would expect a proportionate growth of all dialysis modalities. However, while utilization of HD has progressively increased, there has been a steady decline in PD usage in the United States. Currently less than 7% of the U.S. dialysis patients use PD as their RRT modality.1

PD is associated with patient survival advantages when compared with HD during the first 2 years on dialysis.2-9 Unlike saw-tooth treatment with HD, PD delivers a more steady-state treatment, avoiding fluctuations in plasma volume and solutes, and is generally better tolerated by the patients with cardiovascular compromise. PD provides flexible schedules, thus allowing patients to work, travel, and participate in daytime activities. As PD does not involve needlesticks, patient anxiety is mitigated, arteriovenous access sites for future HD are preserved, and the risk of acquiring blood-borne infections such as hepatitis C and HIV are minimized. Additionally, residual renal function (RRF) is better preserved on PD than HD7-13 and is associated with improved outcomes. Furthermore, patients on PD have better long- and short-term transplant outcomes. Recent data suggest that compared with HD, PD patients have significantly lower incidence of delayed graft function, significantly lower requirement of dialysis in the post-transplant period, and better long-term transplant survival.7, 14-16 Moreover, PD is less expensive than HD on a per-patient per-year basis, with the difference estimated to be more than $20,000 based on the 2010 U.S. Renal Data System (USRDS) annual data report.1

Despite these advantages and lower costs, the number of patients on PD in the United States has progressively declined over the past 10 years17, 18 to below 7% of the total U.S. dialysis population, compared with other developed countries, where PD is being utilized in a much larger (15-30%) proportion of the dialysis population.1

The reasons for low utilization of PD in the United States are complex, but seem to be influenced by psychosocial and economic factors, lack of physician, surgeon, and nursing training, physician bias, and inadequate pre-ESRD education to the patients (Table I

Peritonitis remains a serious complication of peritoneal dialysis. Peritonitis is still a frequent cause of technique failure, and can be associated with death of the patient. Therefore, it is important to establish best demonstrated practices to reduce peritonitis rates to low levels.

Much remains to be learned about preventing peritonitis. The International Society for Peritoneal Dialysis (ISPD) 2005 guidelines on peritoneal dialysis (PD)-related infections included sections on prevention.1 However, because the data are rather limited, the ISPD Standards and Guidelines Committee subsequently felt this would be better presented as a position paper.2 This will soon be published in Peritoneal Dialysis International and will also be freely available to all on the ISPD website (ispd.org). In addition, Guidelines on Prevention and Treatment of Peritonitis in Children are under review and are likely to be available toward the end of 2011 or early 2012 both on the ISPD website and as a publication in Peritoneal Dialysis International. The present paper represents my personal views on preventing peritonitis, but I refer the reader to these important resources.

One of the most important aspects of prevention of peritonitis in PD patients is following the peritonitis rates in a program. This is surprisingly infrequently done; a survey by ISPD nurses of PD programs around the world found that more than 50% did not know the peritonitis rates of their own program.3 A center is not able to evaluate the problem if peritonitis rates are not followed closely, at a minimum yearly, but preferably quarterly. One approach is to have the home training nurse keep track of the peritonitis in a longitudinal fashion by calculating this monthly, and have meetings of at least the physicians caring for the peritoneal dialysis with the nurses to examine the infectious complications in the PD programs and strategize approaches to prevent further episodes approximately quarterly.

The nephrology world should work on standardizing the method of expressing infection rates. While the traditional approach has been to express the rate as months between episodes, a preferable method is to calculate as peritonitis episodes per year at risk. This is done by adding together the sum of the days on peritoneal dialysis of all the patients in a program and then converting this to dialysis years. This then is the denominator of the formula, and the peritonitis episodes are the numerator. For example, if during a single month a center has 25 patients on the entire month (30 days each) and one patient who started during the month (starting the time at risk from the first day of training) and was on PD for 10 days during the month, the time at risk for that month is 25 × 30 + 10 days, or 760 days. Conversion to dialysis years is performed by dividing 760 days by 365 days/year and results in a time at risk of 2.08 years fo

This month, I review three recent studies from the literature addressing issues important to the care of the peritoneal dialysis (PD) patient. A number of core questions related to modality choice center on whether PD offers specific patient-centered outcomes benefits or whether specific PD prescriptions might result in improved hard (non-surrogate) patient-centered outcomes. When considering whether an intervention results in changes in outcomes, the randomized controlled trial (RCT) has been considered the “holy grail,” as when it is performed rigorously the opportunity for the introduction of bias or confounding is minimized. However, the challenges of conducting RCTs with dialysis modality choice are well documented.1

In this literature watch, I review an RCT that highlights additional limitations that might arise from a well-designed RCT of the small size typical of many RCTs in nephrology. Specifically, I consider what might happen if the baseline risk of individuals randomly assigned to the experimental and control treatments differ significantly. Bias is reduced by randomization if sufficient numbers of patients are included in the study such that by chance alone all important baseline prognostic (known and unknown) factors that might influence the outcome are distributed equally to both groups, and that the groups differ only in the intervention under investigation. In small RCTs the equivalence of prognostic characteristics in each arm of the study cannot be assumed.2, 3

Additionally, when addressing the issue of whether a particular clinical finding might predict poorer outcomes or even result in harm, the RCT is not the ideal study design. To identify a factor as potentially harmful and likely to be causal of an adverse outcome, observational findings evaluated in the context of the Bradford-Hill considerations are preferred. In addition to the ethical constraints on conducting an RCT on a question of causation or harm, well-designed observational/epidemiological studies may be most informative because they are conducted under real-world conditions and may include patients expressing the full spectrum of baseline risk. Here too the size of the study population is likely to matter. In this literature watch I review two recent observational studies that interrogate patient databases to provide evidence about potential harm related to a clinical feature or the lack thereof. The first study evaluates the use of PD for initiation of unplanned dialysis compared with an initiation with hemodialysis (HD). In the second observational study, a study exploiting a very large observational database, the authors investigate whether depressed serum albumin levels are similarly associated with mortality in HD and PD patients.

Citation: Takatori Y, Akagi S, Sugiyama H, et al. Icodextrin increases technique survival rates in peritoneal dialysis patients with diabetic nephropathy by impr

Getting Educated

A recent study shows that kidney patients are still not well-informed about peritoneal dialysis as a treatment option. How this can affect outcomes, and what to do about it

In this special issue of D&T, Ramesh Saxena, MD, PhD, points out that the number of U.S. patients who opt for peritoneal dialysis (PD) is on the decline, despite a rise in the incidence of end-stage renal disease (ESRD) and in the use of other renal replacement therapies (RRTs).1 This is surprising, given that PD is often associated with many benefits over other forms of dialysis, including better clinical outcomes, greater scheduling flexibility, and a lower risk of bloodborne infections.

There are many reasons for this state of affairs, but Dr. Saxena places inadequate pre-ESRD education near the top of the list. In another article in this issue, Beth Piraino, MD, writes that improved patient training could help lower the risk of PD-associated peritonitis.2 These observations underscore a larger problem: By and large, patients still are not wellinformed about their treatment choices and how best to prepare for the inevitability of RRT. A recent study confirms this impression.

Lead author Stephen Z. Fadem,MD, clinical professor of medicine at Baylor College of Medicine in Houston, Texas, and colleagues sent emails to 9,000 people whose names appeared in the database of the American Association of Kidney Patients (AAKP). “Ourmain study objective was to better understand patient satisfaction with the scope and quality of dialysis education received before beginningRRT, as well as with their current therapy,” the authors write.3 The 46-question survey covered multiple issues, including satisfaction with current treatment and education before starting therapy, rated on a scale of 1 (extremely dissatisfied) to 7 (extremely satisfied).

Responses were received from 977 people, all of whom had ESRD. Of those patients, about 70% received education about in-center hemodialysis (ICHD) before choosing a therapy, compared with 58% who were told about PD and only 32% who learned about home hemodialysis (HHD). Interestingly, 87% of patients currently undergoing PD reported learning about it prior to choosing treatment, suggesting that most of the people who were educated about this modality selected it.

The mean score for treatment satisfaction for the group as a whole was 5.4 on the 1- to -7 scale. The mean scores for PD and HHD were 5.2 and 5.5, respectively, both significantly higher than the mean of 4.5 reported by people receiving ICHD (p < 0.05). Patients on all three dialysis modalities rated their satisfaction with pre-treatment ICHD education at 4.8; patients currently on PD rated their satisfaction with pre-treatment PD education at 5.8, making them the patientsmost satisfied with the information they received prior to treatment. HHD patients gave their