Science Waking Up to While-You-Sleep Dialysis
Promising research spurs major U.S. study on kidney patients
THURSDAY, April 7, 2005 (HealthDay News) -- Across America, thousands of patients with end-stage kidney disease visit clinics for hours each day while a machine does what their kidneys cannot -- clean their blood of toxins.
Patients chained to this expensive, time-consuming process may be finally getting a break, however: New research suggests home-based, while-you-sleep dialysis does the job better, allowing patients to spend their waking hours doing the things they love.
"We train the patients to administer the therapy at home, but it's essentially the same machine we use in the clinic," explained Canadian researcher Dr. Christopher Chan, medical director of home hemodialysis at Toronto General Hospital.
His team of researchers followed 14 patients with end-stage kidney disease for a year and found "encouraging" results from their use of nighttime home dialysis, with improvements in cardiovascular markers not achieved by standard, three-times-a-week clinic-based dialysis.
"As for survival, we're now at our 10th anniversary of nocturnal hemodialysis in Toronto," he said, with just 10 of 110 patients passing away during that time.
Chan presented his research findings last fall at the annual meeting of the American Society of Nephrology in St. Louis.
These findings, however encouraging, still took place within the context of a small trial without a separate control group, noted Dr. Nathan Levin, medical and research director of the Renal Research Institute, and professor of clinical medicine at Albert Einstein College of Medicine, in New York City.
"Without a control group you can never be sure whether there's selection bias," he pointed out, "and with a small sample size, you can't really be sure of an effect."
That's why the U.S. National Institutes of Health is helping sponsor the first major randomized, controlled study of both nocturnal dialysis and a second alternative protocol, "short daily dialysis," where patients visit the dialysis clinic six times per week, but for an average of just 2 hours a session. In standard, three-times-per-week dialysis, each session usually lasts three to four hours.
Beginning over the next few months, two groups of researchers -- Levin's team in New York, and a team led by Dr. Glenn Chertow, at the University of California, San Francisco -- will compare the 12-month effectiveness of short daily dialysis against standard dialysis, in 300 end-stage kidney disease patients.
At the same time, a third team led by Dr. Michael Rocco, of Wake Forest University in North Carolina, plans to conduct a similar, large study pitting standard therapy against while-you-sleep dialysis in another 300 patients.
According to Levin, short daily dialysis has some advantages over both longer, thrice-weekly dialysis and nocturnal home dialysis. First of all, he said, "it's being done in the clinic -- we know only a fraction of patients can learn how to go home and dialyze themselves."
Short but more frequent dialysis also keeps patient fluid buildup to a minimum, he said. Chronic fluid buildup is highly linked to cardiovascular disease, the major killer of kidney patients.
Finally, because most toxin removal occurs within the first two hours of dialysis, shorter duration treatments shouldn't impair the quality of blood cleansing, Levin said.
Still, for patients who can master at-home dialysis, the while-you-sleep protocol seems the most promising option, some doctors say.
In the Canadian study, and elsewhere, "many claims have already been made" supporting the effectiveness of nighttime dialysis, Levin said. "First, that it lowers blood albumin, a protein which is a very sensitive indicator of outcomes in dialysis patients. It may also increase hemoglobin, another important indicator of survival in cardiac disease," he said.
Chan's research also found that, unlike standard dialysis, sleep-time dialysis prevented the buildup of calcium phosphate within arteries -- a major risk factor for cardiovascular disease in these patients.
"We can stabilize the amount of calcium buildup, at least to a point where we're not seeing the progression that's being seen in the other type of dialysis," Chan said.
Everyone involved in the NIH-funded studies -- the results of which are expected by 2008 -- is hopeful they will replicate the promising results of smaller, earlier trials.
Nocturnal dialysis, especially, would free up patients and greatly improve their quality of life, Chan and Levin said.
Learning to dialyze oneself at home "is a big responsibility," Levin said, but for those who can, "it could obviously be an excellent treatment. Home dialysis in general is a good idea."
To learn more about kidney disease and kidney dialysis, visit the National Institute of Diabetes and Digestive and Kidney Diseases.