Dialysis 6 Times a Week Associated With Lower Cardiovascular Mortality

Rod Franklin

November 22, 2010

November 22, 2010 (Denver, Colorado) — Doubling the frequency of in-center hemodialysis sessions from the traditional 3 sessions per week to 6 sessions per week might lead to increased cardiovascular health for kidney disease patients and slow the dialysis-associated increase in left ventricular mass, a new study suggests.

Researchers from Stanford University in California and the Frequent Hemodialysis Network released the findings of the randomized 3-year clinical trial in conjunction with Renal Week 2010: American Society of Nephrology 43rd Annual Meeting. Results were simultaneously published online November 20 in the New England Journal of Medicine.

Study results do not suggest that all hemodialysis patients can benefit from a regimen of treatment 6 days per week, but they do provide evidence of increased cardiovascular vitality for those who do.

"This is really exciting," said Alan Kliger, MD, clinical professor of nephrology at Yale University, New Haven, Connecticut, and senior author of the study, in an interview with Medscape Medical News. "This is the first randomized controlled study in dialysis in over 30 years to show significant results. Measurements were significantly better with daily dialysis."

To assess the increasing left ventricular mass that dialysis patients can experience, investigators took magnetic resonance images at the beginning and end of 1-year high-frequency dialysis treatment periods to assess increases in mass. They found that left ventricle mass decreased by 13.8% in patients who underwent dialysis 6 times per week instead of the normal 3.

Research also demonstrated that frequent dialysis patients benefited from better scores on a mathematical hazard ratio for death computed to quantify results. The effect of this benefit did not vary significantly for study subgroups according to sex, history of heart disease, anthropometric volume, duration of renal disease, or residual kidney function.

As the prescribed treatment for kidney failure patients over the past 40 years, dialysis is lauded for its ability to mimic functions of the organ and sustain life, but it is also associated with debilitating physical and psychological effects. Scientists hope that more frequent dialysis will act to homogenize the hangover-like cycles of fatigue and recovery typically experienced by patients.

"The theory was that by dialyzing more frequently, the patient could avoid the 'highs' and 'lows' of 3-days-a-week dialysis," said Glenn Chertow, MD, chief of Stanford's nephrology division and coauthor of the study. "Kidneys work 7 days a week, 24 hours a day. You could imagine why people might feel better if dialysis were to more closely mimic kidney function."

The need to more accurately replicate kidney functions is an attitude shared by many nephrologists. Although there has been no therapy identified for most end-stage renal disease patients other than dialysis, the treatment does have a number of clinical drawbacks.

"It doesn't completely replace normal kidney function," said Jonathan Himmelfarb, MD, professor of medicine at the University of Washington in Seattle, and attendee at Renal Week 2010. "It sustains life. It does some of the work that normal healthy kidneys do, but it doesn't do everything. We're simply not as good as nature." Stepping up treatment frequency might partly make up for some failings of dialysis.

Other positive results from the study show that scheduling sessions more often can improve control of hypertension and hyperphosphatemia and can improve patient scores on the RAND-36 physical-health composite scale.

The Stanford-led trial revealed that frequent dialysis had no significant effects on cognitive performance, self-reported depression, serum albumin concentration, or use of erythropoiesis-stimulating agents. Moreover, patients who underwent treatments 6 times weekly were more likely to require interventions related to vascular access.

In their published observations, Dr. Kliger and colleagues cite a number of serious health complications associated with hemodialysis that need to be addressed. Patient morbidity remains high, and frequent complications include those related to heart disease, hypertension, anemia, bone disease, poor nutrition, inflammation, depression, and impaired cognitive and physical function.

The trial, a collaborative effort of 11 university-based and 54 community-based hemodialysis facilities in North America, enrolled a total of 378 patients between January 1, 2006 and March 31, 2009. Of these, 245 patients were randomized into 2 groups for dialysis study — those who continued to undergo in-center hemodialysis 3 times a week and those who underwent it 6 times a week.

Baseline characteristics of the groups were similar, and characterized by diversity with respect to age, sex, race or ethnic group, the primary cause of kidney disease, coexisting conditions, income, and education. Patients had end-stage renal disease for a median of 3.6 years. Of those assigned to hemodialysis 6 times per week, 78% attended at least 80% of the prescribed sessions.

Although the study suggests that dialysis is characterized by a measurable margin of improvement that conceivably can be filled, the authors acknowledge that major changes in practice cannot be recommended until the net effects of frequent hemodialysis are balanced against the added burden for the patient and societal expense.

"You have to factor in the burden of additional sessions, the travel, and the cost," Dr. Chertow said.

In an editorial also published online November 20 in the New England Journal of Medicine, Zbylut J. Twardowski, MD, PhD, and Madhukar Misra, MD, from the Division of Nephrology, Department of Medicine, University of Missouri, Columbia, write: "This randomized, controlled trial, which took a decade to complete, did show that frequent dialysis was better with respect to control of hypertension and control of hyperphosphatemia. Furthermore, it was associated with favorable changes in the coprimary composite outcomes of death or change (from baseline to 12 months) in left ventricular mass, as assessed by cardiac magnetic resonance imaging, and death or change in the physical-health composite score of the RAND 36-item health survey."

"Whether the more frequent vascular-access and clotting issues would be increasingly problematic over time is not known," Drs. Twardowski and Misra note. "Whether patients would do even better at home is also unclear."

Renal Week 2010: American Society of Nephrology 43rd Annual Meeting. Presented November 20, 2010.


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