Effects of Dialysis Type on Survival in Patients with End-Stage Kidney Disease

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The summary below is from the full report titled "Comparing the Risk for Death with Peritoneal Dialysis and Hemodialysis in a National Cohort of Patients with Chronic Kidney Disease." It is in the 2 August 2005 issue of Annals of Internal Medicine (volume 143, pages 174-183). The authors are B.G. Jaar, J. Coresh, L.C. Plantinga, N.E. Fink, M.J. Klag, A.S. Levey, N.W. Levin, J.H. Sadler, A. Kliger, and N.R. Powe.

What is the problem and what is known about it so far?

Kidneys are the organs that filter out waste products and water from the blood. When kidneys fail to function, dialysis can clean waste products artificially. There are 2 forms of dialysis: a kidney machine that filters the blood (hemodialysis) and an exchange process that uses the lining of the inside of the abdomen as a filter (peritoneal dialysis). In peritoneal dialysis, a cleansing liquid drains from a bag into the abdomen through a tube. Waste products and water pass through the lining of the abdomen into the liquid. The waste-filled liquid is then drained from the abdomen.

Doctors may recommend either type of dialysis for patients with end-stage kidney disease. Some studies suggest, however, that patients who get peritoneal dialysis differ in several ways from those who get hemodialysis. Also, there is controversy about which type of dialysis offers a survival advantage.

Why did the researchers do this particular study?

To compare the risk for death with peritoneal dialysis versus hemodialysis.

Who was studied?

1041 adults with newly diagnosed end-stage kidney disease (274 receiving peritoneal dialysis and 767 receiving hemodialysis). Their average age was about 55 years.

How was the study done?

During October 1995 to June 1998, the researchers recruited patients with newly diagnosed kidney failure from 81 dialysis clinics in 19 states. Patients answered questions about their health behaviors, medical history, and social support and had multiple laboratory tests. The researchers then followed outcomes of patients for up to 7 years.

What did the researchers find?

Twenty-five percent of the patients receiving peritoneal dialysis and 5% of those receiving hemodialysis switched to the other dialysis type during follow-up. Patients starting treatment with peritoneal dialysis appeared healthier than did those starting treatment with hemodialysis. Also, more of them were high school graduates, were married, and were employed. Analyses that adjusted for these differences found statistically significantly higher risks for death among patients receiving peritoneal dialysis compared with those receiving hemodialysis during the second, but not first, year of dialysis.

What were the limitations of the study?

The study was not a randomized trial.

What are the implications of the study?

Although patients with end-stage kidney disease who get peritoneal dialysis may be healthier than other patients when they start treatment, they frequently switch to hemodialysis. Continuing peritoneal dialysis over time might be associated with increased risk for death.