Will Innovations in Dialysis Improve Dialysis Care?

Dialysis treatments for patients with end-stage renal disease (ESRD) have been much the same for 30 years or more. Patients receive hemodialysis 3 times a week for several hours or continuous peritoneal dialysis with intermittent 2-L exchanges. Mortality rates have declined since 1984 for all ESRD patients, with improved survival rates among both dialysis and kidney transplant patients.1 One stubborn subgroup has resisted this improvement, hemodialysis patients in their first year of treatment. The mortality rate of patients during year 1 of dialysis has remained constant since 1992. Allan Collins has shown that the first-year hemodialysis death rates adjusted for age, gender, race, and primary cause of ESRD have remained unchanged in every age category since 15 years ago.

Why do these first-year hemodialysis death rates remain high? The National Cooperative Dialysis Study published more than 30 years ago showed that survival was related to time on dialysis and urea removal, leading to a focus on urea kinetics to define dialysis adequacy.2 However, subsequent randomized controlled studies for both hemodialysis3 and peritoneal dialysis4 failed to show improved survival with higher Kt/V urea. Perhaps it is time to broaden our view and consider changes in addition to improved urea removal to standard dialysis to improve outcomes.

In this issue of Advances in Chronic Kidney Disease, we explore several dialysis innovations with promise to improve the lives of ESRD patients. In 1983, Charra et al5 described their experience in Tassin, France, with longtime, slow ultrafiltration dialysis. The level of blood pressure control and the survival rate were dramatic. In this issue, Troidle and colleagues describe their experience with hemodialysis performed overnight, in center, and 3 times a week.6 Quality of life was not adversely affected by spending the night sleeping in a dialysis center. Urea and phosphate removal increased, as did total fluid removal, but with a lower ultrafiltration rate. A recent publication from the Dialysis Outcomes Practice Patterns Study7 shows that this lower rate of ultrafiltration may provide a survival advantage. Rocco reviews the published studies on short daily and long nocturnal daily hemodialysis.8 Some observational studies suggest improvements in outcomes such as blood pressure control, left ventricular hypertrophy, phosphate level, anemia management, sleep apnea. and quality of life. He describes the current randomized clinical trials comparing daily in-center hemodialysis and long nocturnal hemodialysis to standard 3-times-a-week treatments.9 Anantharam and Moss provide an ethical analysis of whether Medicare should pay for daily dialysis given the current state of our knowledge.10 Sowinski and Decker investigate new ways of thinking about drug dosing with more frequent dialysis regimens.11

Wystrychowski and Levin address the challenge of defining and achieving “dry weight” for dialysis patients. Their observations are particularly cogent in a population with a high incidence of left ventricular hypertrophy and high cardiovascular mortality. They describe new methods to better estimate dry weight and achieve more normal fluid balance.12 Ouseph and Ward describe the importance of ultrapure dialysate water and the challenges to provide such dialysate in the home environment.13 Ronco and Cruz discuss hemodiafiltration, combining diffusion and convection to increase solute removal. They describe several innovations to this technique that combine biocompatible membranes and ultrapure fluid to prevent inflammation and remove larger molecules such as advanced glycosylation end products and leptin. They review the published clinical effects of hemodiafiltration on mortality, quality of life, anemia, dialysis-related hypotension, and amyloidosis.14 Hamlett and Haragsim explore the impact of more frequent dialysis on inflammation associated with chronic kidney disease.15

In addition, we consider innovations in the world of peritoneal dialysis on the quality of life with kidney failure. Currently, approximately 7% of all dialysis patients in the United States use peritoneal dialysis as their form of renal replacement therapy.1 Moran shows that with an early and thorough educational program, nearly half of the patients with stage IV chronic kidney disease will choose a home-based over an in-center–based therapy.16 Pollock et al re-examine the controversial subject of early-start dialysis with regard to mortality, morbidity, preservation of kidney function, and economic cost. They conclude that answers to these issues will be even clearer in 2009 with the results of the Initiating Dialysis Early and Late Study, which has enrolled over 800 patients thus far.17 Povlsen and Ivarsen study the use of assisted peritoneal dialysis in various parts of the globe for the ever-increasing population of frail elderly patients on dialysis.18 Holmes analyzes the current state-of-the-art of peritioneal dialysis solutions and suggests possible future solutions containing everything from carnitine to sulodexide.19 Mujais and Story present new data on optimal peritoneal dialysis prescriptions by using a large database of cycler prescriptions. They describe the impact of cycle length on infusion and/or drain pain, alarm frequency, and treatment efficacy.20 Finally, Rastogi and Nissenson look into the crystal ball for future dialysis. They describe the exciting advances in nanotechnology, nanoelectronics, microfluidics, living and bioartificial membranes, and stem cells that are helping to design renal replacement treatments for the future. These truly innovative techniques may help create the next generation of treatments for ESRD patients.21

We hope that a new focus on better treatment, with innovative dialysis regimens, improved dialysate water and less inflammation, hemodiafiltration in addition to standard hemodialysis, achievement of true dry weight, and improved delivery of peritoneal dialysis will result in longer survival and improved quality of life for our patients. The next generation of renal replacement, using nanotechnology, microfluidics, and living membranes, may help realize the dream of a truly continuous, artificial kidney.