The number of people in the United States with kidney failure is dramatically increasing. Currently, more than 400,000 Americans are being treated for end-stage renal (kidney) disease (ESRD) with dialysis or kidney transplantation. And it is estimated that this number will exceed two million by 2030, largely due to the increase in diabetes , which is the leading cause of kidney failure.

The kidneys filter waste products and water from the blood. When they fail, people must undergo either dialysis or kidney transplantation in order to survive. Since the waiting lists for kidney transplants are very long, most people with ESRD must undergo dialysis, which filters the blood artificially.

There are two basic types of dialysis: hemodialysis and peritoneal dialysis. In hemodialysis, a machine collects blood from a vein, filters out waste, and returns the cleansed blood back into the body. This generally takes 3-4 hours and must be repeated three times per week. In peritoneal dialysis, a catheter tube permanently implanted into the abdomen injects waste-absorbing fluid into the peritoneal cavity, which surrounds the abdominal organs. The fluid remains in the abdomen for two to six hours before it is drained, and the procedure must be repeated 4-6 times a day.

The choice of which type of dialysis to use is usually up to a patient and his/her physician, and is based on the patient’s lifestyle. But a new study in the August 2, 2005 issue of the Annals of Internal Medicine found that the risk of dying in the second year of dialysis was twice as high among patients undergoing peritoneal dialysis, compared with those undergoing hemodialysis.

About the Study

This study included 1,041 people with ESRD who were receiving dialysis treatment at one of 81 clinics. The researchers used questionnaires and examined medical records to obtain information about the participants’ health behaviors and medical history.

Then the researchers followed the participants for up to seven years to compare the risk of death among the group of patients undergoing hemodialysis (767) with the group undergoing peritoneal dialysis (274).

The Findings

After an average follow-up of 2.4 years, 21% of the participants undergoing peritoneal dialysis and 24% of those undergoing hemodialysis died.

In the first year of treatment, the risk of death did not differ between the two groups. But in the second year, the participants undergoing peritoneal dialysis had a 2.34 times greater risk of death than those undergoing hemodialysis.

Interestingly, in participants with cardiovascular disease (e.g., congestive heart failure, heart rhythm disturbances, hypertension), those undergoing peritoneal dialysis were twice as likely to die than those undergoing hemodialysis. The risk of death in participants without cardiovascular disease, however, was not affected by type of dialysis.

This study is limited because it was not a randomized, controlled trial. Instead of randomly assigning participants to receive hemodialysis or peritoneal dialysis, the researchers left the choice up to the participants and their doctors. For this reason, participants who chose peritoneal dialysis were fundamentally different than those who chose hemodialysis, making it likely that factors other than the type of dialysis affected the risk of death.

How Does This Affect You?

These results suggest that choosing peritoneal dialysis over hemodialysis may increase the risk of death in some people with ESRD, especially those with cardiovascular disease. However, since these results do not align with previous research on the topic, this study alone will not likely change practice. Randomized clinical trials would provide more reliable answers regarding which type of dialysis is most beneficial for which populations.

When considering which type of dialysis to use, it is important to take a close look at the risks versus benefits of each choice. Depending on a person’s individual preferences and lifestyle factors, choosing one type of dialysis over the other becomes a quality of life decision. Since dialysis becomes such a major part of a person’s life, quality of life must be considered in addition to health outcomes.

There are a number of dialysis treatment options available today, and more advanced treatments are on the horizon. If you need dialysis – either indefinitely or while waiting for a donor kidney – your physician can help you figure out which type would be the most acceptable and beneficial for you.