Overnight procedure allows longer filtering, which experts prefer
THURSDAY, May 21 (HealthDay News) -- Nighttime dialysis, done while people are asleep, not only frees up time during their days but is probably better for their health as well, a new study suggests.
Although lifesaving, dialysis is time-consuming and often inconvenient for those who need it. Nighttime dialysis, a newer option, actually takes longer but is done while a person sleeps.
"The concept is simple," explained Dr. Robert Provenzano, chief of nephrology at St. John Hospital and Medical Center in Detroit. "Since normally our kidneys work 24 hours a day, seven days a week, the more time you spend with your blood being cleaned, the better it is for you metabolically."
"The current study is a small study, but it does show that these patients do have cleaner blood and their blood counts are better," Provenzano said. "It's consistent and supportive of U.S. studies that have shown the same or improved outcomes for nighttime dialysis."
For the study, British researchers compared 53 people who underwent overnight hemodialysis for at least a year to 53 similar people who had regular daytime dialysis. Most participants were men, diabetes was present in 17 percent of the overnight group and 13 percent of the others, and participants averaged 50 years old in the overnight group and 52 in the daytime group.
Overnight dialysis took six to seven hours a session and was given three times a week, whereas conventional, or daytime, dialysis took four to five hours a session and was given three times weekly.
Although the results weren't dramatic, the study found that long overnight dialysis improved certain outcomes. For example, there was a trend toward needing fewer phosphate-binding tablets, which means the longer dialysis was doing a better job filtering the blood.
The findings are published online in the Clinical Journal of the American Society of Nephrology.
"I think this study is encouraging," said Dr. Orly Kohn, a nephrologist and medical director of home dialysis at the University of Chicago Medical Center. "It shows that overnight dialysis is safe and it's doable."
Kohn said she thinks the results probably would have been even more positive if the overnight dialysis had been given frequently. For example, she said, people who do overnight dialysis at home usually do it six nights a week.
"The general impression of nephrologists is that longer dialysis is better," Kohn said. "The fluid removal rate is slow, and it's the fluid removal that causes a lot of the side effects from dialysis."
Additionally, she said, the comparison group in the study received four to five hours of dialysis each session, whereas many people in the United States receive about three hours per session. So, if the researchers had compared people who were getting nine hours of conventional dialysis with those receiving 21 hours of overnight dialysis, the differences likely would have been greater, she said.
"People who dialyze every day get in a lot more dialysis, plus they have their down time at home rather than in a dialysis center," Provenzano said. "They can read, watch TV, whatever. It makes a huge difference in their lives. Plus, they can eat and drink more liberally, and their blood pressure and blood counts are better."
He advised people to "pick a therapy that fits your lifestyle, while attempting to maximize the time you're on the machine, whether that's in-center nighttime dialysis or at-home dialysis."
The Kidney Foundation has more on dialysis at home.
SOURCES: Robert Provenzano, M.D., chief, nephrology, St. John Hospital and Medical Center, Detroit; Orly Kohn, M.D., nephrologist, and medical director, Home Dialysis Unit, University of Chicago Medical Center, Chicago; May 21, 2009, Clinical Journal of the American Society of Nephrology, online
All rights reserved