Portal de Periódicos da CAPES

Learning about the practice of peritoneal dialysis

2009; Elsevier BV; Volume: 76; Issue: 1 Linguagem: Inglês

10.1038/ki.2009.65

1523-1755

Thomas A. Golper,

Healthcare cost, quality, practices

Observational studies are valuable and provocative. We are learning about how we practice peritoneal dialysis (PD) and how we might improve on that practice. For example, outcomes of PD therapy are not worse in large patients. Perhaps this will encourage physicians and patients to utilize PD in large patients. In addition, better descriptions of how we practice will help to identify systematic barriers to the advancement of home dialysis. Observational studies are valuable and provocative. We are learning about how we practice peritoneal dialysis (PD) and how we might improve on that practice. For example, outcomes of PD therapy are not worse in large patients. Perhaps this will encourage physicians and patients to utilize PD in large patients. In addition, better descriptions of how we practice will help to identify systematic barriers to the advancement of home dialysis. Knowledge of peritoneal anatomy and physiology is constantly being applied to how we prescribe and perform peritoneal dialysis (PD). Also important is the general comprehension of how we implement this therapy. Mehrotra and colleagues1.Mehrotra R. Chiu Y.-W. Kalantar-Zadeh K. et al.The outcomes of continuous ambulatory and automated peritoneal dialysis are similar.Kidney Int. 2009; 76: 97-107Abstract Full Text Full Text PDF PubMed Scopus (95) Google Scholar (this issue) utilized the United States Renal Data System (USRDS) to describe how American nephrologists practice PD. Using the years 1996–1998 as a reference, they compared changes in PD practice in 1999–2001 and 2002–2004. Their findings regarding the cornucopia of material in the data set are just the tip of the iceberg. Quite probably, many more papers are in preparation from the present analyses, generously shared with us now to whet our appetite. The theme of the work of Mehrotra et al.1.Mehrotra R. Chiu Y.-W. Kalantar-Zadeh K. et al.The outcomes of continuous ambulatory and automated peritoneal dialysis are similar.Kidney Int. 2009; 76: 97-107Abstract Full Text Full Text PDF PubMed Scopus (95) Google Scholar is the comparison of outcomes utilizing continuous ambulatory PD (CAPD) versus automated PD (APD). In short, outcomes were similar. The initial question of CAPD versus APD outcomes arose because overall outcomes of PD improved, and simultaneously, the prevalence of APD rose over that of CAPD. The authors sought to define or refute a cause and effect. What the authors have not discussed yet are the other practice variables that affect the utilization of CAPD versus APD in the United States. A drill down on the data may yield that fruit. APD is slightly more expensive than CAPD, for several reasons. First, the cycler has to be purchased or leased. Second, in general, greater solution volumes are needed, albeit in larger, more cost-efficient bags. Third, cycler training plus manual training for APD takes longer than mere manual exchange training for CAPD. Lastly, the more expensive icodextrin solution is more likely to be used in APD for the long dwell than it is in CAPD's long dwell. So if APD is more expensive than CAPD, why is it becoming more prevalent? There is more training revenue to the dialysis facility with the extended training required for APD. This revenue exceeds that of monthly supervision fees. However, I do not think this is the driver of the popularity of APD. In my opinion, the answer is simple and, quite frankly, refutes the attacks on for-profit large dialysis organizations. Patients prefer it, and providers accommodate patient preferences at the potential expense of profit margins (lost because of the use of more fluids). At the start of the observation period of Mehrotra et al.1.Mehrotra R. Chiu Y.-W. Kalantar-Zadeh K. et al.The outcomes of continuous ambulatory and automated peritoneal dialysis are similar.Kidney Int. 2009; 76: 97-107Abstract Full Text Full Text PDF PubMed Scopus (95) Google Scholar (1996–1998), most American PD programs were training patients for just CAPD. Then, toward the completion of training or, far more likely, several months later, patients were retrained for APD. At that time, the peritoneal equilibration test and comparable peritoneal transport assessment tests were just being routinely administered, and these transport-status tests were rarely the determining factor in deciding between CAPD and APD. As we went forward and became more familiar with how to use peritoneal equilibration test data, and as transport status and behavior became better understood, more patients in higher transport-status categories were urged to consider APD. Thus, APD grew as a result of patient preference related to lifestyle, as well as in response to the emphasis to direct higher transporters toward APD. So while Mehrotra et al.1.Mehrotra R. Chiu Y.-W. Kalantar-Zadeh K. et al.The outcomes of continuous ambulatory and automated peritoneal dialysis are similar.Kidney Int. 2009; 76: 97-107Abstract Full Text Full Text PDF PubMed Scopus (95) Google Scholar considered the role of ascertainment bias in their results, I think the movement of higher transporters to APD was secondary to the major determinant—lifestyle preferences. A follow-up study could explore when the first peritoneal equilibration test was performed relative to the decision to use APD rather than CAPD. Unfortunately, data such as these are sometimes not in the USRDS database. Another area touched on by Mehrotra et al.1.Mehrotra R. Chiu Y.-W. Kalantar-Zadeh K. et al.The outcomes of continuous ambulatory and automated peritoneal dialysis are similar.Kidney Int. 2009; 76: 97-107Abstract Full Text Full Text PDF PubMed Scopus (95) Google Scholar is the outcome relative to the size (translate as ‘experience’) of the PD program. The authors could demonstrate an improvement in technique survival only with larger programs. I was critical of the way these data were analyzed and urge further study of the same data set. I have expressed that to the authors. If outcomes other than just technique survival are superior in larger programs, then, in my opinion, this supports the consolidation of programs to take advantage of the benefits of experience. In Canada, Europe, Asia, and elsewhere, PD programs are much larger in patient census than are typical American programs. Mehrotra himself, with other colleagues, has described the problems inherent in small PD programs, especially in training young nephrologists.2.Mehrotra R. Blake P. Berman N. et al.An analysis of dialysis training in the United States and Canada.Am J Kidney Dis. 2002; 40: 152-160Abstract Full Text Full Text PDF PubMed Scopus (101) Google Scholar Consolidation of several smaller programs into a larger program was done in Phoenix, Arizona, with positive effects. So if larger programs produce better results and consolidation is achievable, there may be momentum to consolidate. Competition seems a likely barrier to this at present, but large dialysis organizations could assist in an initiative to consolidate several small PD programs within their organization in a convenient geographic area. Yet another area mentioned by Mehrotra et al.1.Mehrotra R. Chiu Y.-W. Kalantar-Zadeh K. et al.The outcomes of continuous ambulatory and automated peritoneal dialysis are similar.Kidney Int. 2009; 76: 97-107Abstract Full Text Full Text PDF PubMed Scopus (95) Google Scholar is the ‘protective’ effect of larger body mass index, a concept I call the ‘Godzilla effect’ (size does matter). Because the paper's focus is on CAPD versus APD, this topic is not discussed in any detail. In hemodialysis patients, larger body mass index is clearly a survival advantage in observational studies,3.Stack A.G. Murthy B.V.R. Molony D.L. Survival differences between peritoneal dialysis and hemodialysis among ‘large’ ESRD patients in the United States.Kidney Int. 2004; 65: 2398-2408Abstract Full Text Full Text PDF PubMed Scopus (92) Google Scholar, 4.Port F.K. Ashby V.B. Dhingra R.K. et al.Dialysis dose and body mass index are strongly associated with survival in hemodialysis patients.J Am Soc Nephrol. 2002; 13: 1061-1066PubMed Google Scholar, 5.Lowrie E.G. Zhensheng L.I. Ofsthun N. et al.Measurement of dialyzer clearance, dialysis time, and body size: death risk relationships among patients.Kidney Int. 2004; 66: 2077-2084Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar whereas in PD patients, the argument is unresolved, with conflicting observations.3.Stack A.G. Murthy B.V.R. Molony D.L. Survival differences between peritoneal dialysis and hemodialysis among ‘large’ ESRD patients in the United States.Kidney Int. 2004; 65: 2398-2408Abstract Full Text Full Text PDF PubMed Scopus (92) Google Scholar, 6.Abbott K.C. Glanton C.W. Trespalacios F.C. et al.Body mass index, dialysis modality, and survival: analysis of the United States Renal Data System Dialysis Morbidity and Mortality Wave II study.Kidney Int. 2004; 65: 597-605Abstract Full Text Full Text PDF PubMed Scopus (221) Google Scholar, 7.Snyder J.J. Foley R.N. Gilbertson D.T. et al.Body size and outcomes on peritoneal dialysis in the United States.Kidney Int. 2003; 64: 1838-1844Abstract Full Text Full Text PDF PubMed Scopus (139) Google Scholar The analysis of Mehrotra et al.1.Mehrotra R. Chiu Y.-W. Kalantar-Zadeh K. et al.The outcomes of continuous ambulatory and automated peritoneal dialysis are similar.Kidney Int. 2009; 76: 97-107Abstract Full Text Full Text PDF PubMed Scopus (95) Google Scholar updates the previous USRDS data with what appears to be the largest data set examined to date. Patients with a larger body mass index require more dialysis to achieve the same level of solute removal when normalized to size. That leads to more fluids (and expense), more exchanges (and peritonitis risk), and perhaps a dissuasion from even attempting PD. The findings that larger PD patients have a survival advantage over smaller patients may encourage the use of PD in larger patients previously precluded from the therapy. Whenever dialysis patient outcome and body size are considered, it raises a major unanswered question: What is the best normalizing factor in measuring the dose of delivered dialysis?8.Tzamaloukas A.H. Malhotra D. Murata G.H. Gender, degree of obesity, and discrepancy between urea and creatinine clearance in peritoneal dialysis.J Am Soc Nephrol. 1998; 9: 497-499PubMed Google Scholar Could we use this data set to address this? Mehrotra et al.1.Mehrotra R. Chiu Y.-W. Kalantar-Zadeh K. et al.The outcomes of continuous ambulatory and automated peritoneal dialysis are similar.Kidney Int. 2009; 76: 97-107Abstract Full Text Full Text PDF PubMed Scopus (95) Google Scholar show that outcomes have improved over the 9-year observation period. The (US) National Kidney Foundation's original Dialysis Outcomes Quality Initiative (DOQI), formed in 1995, published peritoneal dialysis adequacy guidelines in 1997 and updated them in 2000, and again in 2006. Although mentioned only in passing by Mehrotraet al.,1.Mehrotra R. Chiu Y.-W. Kalantar-Zadeh K. et al.The outcomes of continuous ambulatory and automated peritoneal dialysis are similar.Kidney Int. 2009; 76: 97-107Abstract Full Text Full Text PDF PubMed Scopus (95) Google Scholar it seems likely that these DOQI guidelines influenced the practice of PD in the United States and may be part of the explanation for the improvement noted by Mehrotra et al.1.Mehrotra R. Chiu Y.-W. Kalantar-Zadeh K. et al.The outcomes of continuous ambulatory and automated peritoneal dialysis are similar.Kidney Int. 2009; 76: 97-107Abstract Full Text Full Text PDF PubMed Scopus (95) Google Scholar First, if DOQI PD adequacy guidelines had discouraged physicians from offering PD to patients considered marginal, then outcomes might have improved merely because of a selection bias. This would be considered an unintended consequence of the guidelines. An intended consequence would be that the guidelines were, in fact, utilized and educated physicians, dialysis staff, patients, and payers, leading to an improved practice of PD. Both explanations are quite plausible. Over the time course of the study by Mehrotra et al.,1.Mehrotra R. Chiu Y.-W. Kalantar-Zadeh K. et al.The outcomes of continuous ambulatory and automated peritoneal dialysis are similar.Kidney Int. 2009; 76: 97-107Abstract Full Text Full Text PDF PubMed Scopus (95) Google Scholar patients initiated dialysis at progressively higher estimated glomerular filtration rates (USRDS 2004 Annual Data Report, Figures 3.28 and 3.299.United States Renal Data System 2004 Annual Data Report National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, USA2004Google Scholar). Is this lead-time bias the explanation for the improved outcomes?10.Korevaar J.C. Jansen A.M. Dekker F.W. et al.When to initiate dialysis: effect of proposed US guidelines on survival.Lancet. 2001; 358: 1046-1050Abstract Full Text Full Text PDF PubMed Scopus (176) Google Scholar I personally think not, as the earlier initiation at higher glomerular filtration rates reflects comorbidities and the hope that starting dialysis will salvage patients who are ill from their comorbidities, not uremia (USRDS 2003 Annual Data Report, Figure 3.27;11.United States Renal Data System 2003 Annual Data Report National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, USA2003Google Scholar USRDS 2004 Annual Data Report, Table 3b9.United States Renal Data System 2004 Annual Data Report National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, USA2004Google Scholar). This question of earlier initiation of dialysis will be addressed later this year with the analysis and report of the Initiating Dialysis Early and Late (IDEAL) trial.12.Cooper B.A. Branley P. Bulfone L. et al.The Initiating Dialysis Early and Late (IDEAL) study: study rationale and design.Perit Dial Int. 2004; 24: 176-181PubMed Google Scholar Home dialysis is at a crossroads in the United States. The incident dialysis population is older and carries more comorbidities than ever in the history of the End-Stage Renal Disease Program. Such a patient population is unlikely to seek self-care dialysis at home. On the other hand, the shortage of dialysis nurses and the prevalence of infections with in-center dialysis units are stimuli to send patients home. Yet there are many systematic barriers to the advancement of home dialysis. A brief list of these is shown in Table 1. The North American chapter of the International Society for Peritoneal Dialysis is spearheading an initiative to publicize these barriers such that all stakeholders can participate in overcoming them and, by doing so, advance the utilization of all home dialysis therapies.Table 1Systematic barriers to home dialysis in the United StatesGovernmental/Medicare Centers for Medicare and Medicaid Services requirements for visits and reimbursements Reimbursement strategies favoring graft placement instead of fistulae Lack of home-care partner support Delays in accreditation and certification of new unitsEducational issues Inadequate patient education about home therapies Inadequate physician education/training/experience in home dialysis Inadequate dialysis-staff education/training/experience in home dialysisAttitude/philosophy of large dialysis organizations Availability of state-of-the-art equipment and solutions Delivery of products/supplies Pharmacy preparations readily available Business conflicts trumping patient care Failure of laboratory services to accommodate home dialysis needs Use of data for commercial advantage rather than for practical improvements Treatment of home dialysis clinic as an addendum to in-center hemodialysis, especially regarding physical environment and staffing Open table in a new tab So observations that describe how we practice can be exceedingly useful and provocative. We must continue to encourage such investigations, including a more in-depth analysis of the current Mehrotra et al. data set.1.Mehrotra R. Chiu Y.-W. Kalantar-Zadeh K. et al.The outcomes of continuous ambulatory and automated peritoneal dialysis are similar.Kidney Int. 2009; 76: 97-107Abstract Full Text Full Text PDF PubMed Scopus (95) Google Scholar Thomas A. Golper has received speaking honoraria and consultation fees from Baxter Healthcare, Fresenius North America, and DaVita.