Overnight Dialysis Saves Lives: Study

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By Alan Mozes
HealthDay Reporter

FRIDAY, Nov. 7 (HealthDay News) -- Dialysis for eight hours a night, three times a week, reduced the risk of death for kidney patients by nearly 80 percent, compared to conventional, four-hour dialysis three times a week, a new study found.

This type of improvement is important and necessary, the study's lead author said. "Unfortunately, the mortality rate of patients treated by conventional four hours, three times weekly hemodialysis remains unacceptably high, despite several improvements in dialysis technology and general medical care," said Dr. Ercan Ok, who's with the department of nephrology at Ege University, in Izmir, Turkey.

"As an alternative, more frequent and/or longer hemodialysis regimens seem promising," added Ok, who presented the findings Nov. 7 at the American Society of Nephrology's annual meeting, in Philadelphia.

Dialysis, sometimes called hemodialysis, can be performed as either an inpatient or outpatient procedure, although it's usually administered at a medical facility of some kind. The treatment, which extracts waste products from the blood, such as potassium and urea, is the most common means of fluid removal intervention for kidney-failure patients.

Most patients who undergo dialysis do so on a thrice weekly schedule for between three to five hours per treatment, according to the U.S. National Institute of Diabetes and Digestive and Kidney Diseases.

For the new study, Ok and his colleagues tracked 224 Turkish dialysis patients -- average age, 45 -- who were switched from conventional dialysis to a routine of three nights a week, eight hours per session at a dialysis center. The researchers noted that the patients generally experienced a month-long "adaptation period," after which they were able to sleep during their treatments.

After one year, the researchers compared the overnight group with a similar pool of patients who maintained the typical regimen of four hours of treatment, three days a week.

The overnight patients experienced a 78 percent drop in mortality compared with standard patients. Also, overnight patients experienced marked improvements in blood pressure control, which translated into a two-thirds drop in the use of blood pressure medications.

And, levels of the mineral phosphate declined toward normal levels among the overnight dialysis patients, which led to a 72 percent decline in the use of drugs to lower phosphate absorption.

The overnight patients also reported increased appetite, desirable weight gain, and a boost in blood protein levels.

What's more, many of the overnight patients returned to work, reported improved job performance and had better mental functioning.

"We expect that these data would be convincing to the whole society -- including physicians, patients, health authorities, and social security institutions -- for the necessity of longer hemodialysis in order to improve high mortality and morbidity," Ok said.

Dr. Robert Provenzano, chairman of the department of nephrology at St. John Hospital and Medical Center in Detroit, said that while the study "has merit, it needs to be validated."

"What we do know for a fact is that more dialysis is better. That should be intuitive, since your kidneys work seven days a week, 24 hours a day," he said. "And data from Europe and even the U.S. looking at more frequent dialysis has already shown improvements across the board: in cardiovascular status, anemia, blood pressure, a better sense of well-being, and less hospitalization."

"But the problem here is that in this study, the patients were self-selected," Provenzano added. "So it's not a randomized, controlled study. Which might mean that the findings may be almost too good to believe. Since in developing countries, such as Turkey, China, India, patients who receive this kind of procedure, which all-comers receive in the U.S., tend to be wealthier and healthier. And we don't know how that fact would impact on these results. So what we need now is more randomized research."