Intensive Dialysis Doesn't Save Lives of the Sickest
By Amanda Gardner
HealthDay Reporter on 10/21/2009
WEDNESDAY, Oct. 21 (HealthDay News) -- Giving seriously ill patients high-intensity dialysis is no better at saving lives or speeding recovery than a lower-intensity version of the same treatment, new research shows.
The patients in question were the sickest of the sick; all were in hospital intensive care units (ICUs).
"Approximately half had overwhelming infection, causing multiple body organs to fail. Others had complications following major surgery, most commonly for heart surgery, and some were admitted to ICU following severe trauma or injury," explained Dr. Alan Cass, co-author of the study published in the Oct. 22 issue of the New England Journal of Medicine.
"Findings from previous, smaller studies had suggested that intensive dialysis treatment for people with severe acute kidney injury saved lives," said Cass, director of the renal and metabolic division at the George Institute for International Health in Sydney, Australia. "This study, consistent with the findings of another recent large trial, found no benefit with intensive dialysis over standard dialysis treatment. No benefit was seen in terms of reduction in deaths or length of time in hospital, nor was there any difference in the need for ongoing and costly dialysis support."
"The two doses they chose -- so-called standard or a higher dose -- really didn't make any difference in outcome and that clarifies previous papers, some of which said the more you gave the better," added Dr. Kevin Martin, chief of nephrology at Saint Louis University School of Medicine.
According to background information in the paper, about 5 percent of patients in hospital ICUs have kidney injury severe enough to warrant dialysis. Of these, 60 percent will die.
But it's been unclear which dialysis approach is best.
For this study, 1,508 acutely ill patients were randomized to receive either a high-intensity or low-intensity version of continuous renal-replacement therapy.
"About three-quarters [of patients] were on ventilators, and most also needed continuous medication to support their heart and blood pressure, in addition to needing dialysis to simply stay alive," Cass said.
Continuous dialysis filters more slowly than intermittent dialysis, which is performed once every other day or every three days.
After 90 days, the mortality rate in the two groups was the same: 44.7 percent. The authors discerned no major differences in how long patients had to stay on dialysis, in rates of organ failure, need for mechanical ventilation or length of stay in either the ICU or the hospital.
The authors stressed, however, that a certain threshold of intensity did need to be reached to see any benefit. It's just that anything beyond this threshold is unlikely to bring any added value.
"A higher-dose therapy probably doesn't really change anything and there is probably no need to go that far or to that expense. It doesn't change the outcome," Martin said.
Although Cass predicted the results would "strongly influence current practice," that likely depends on geography, as different areas of the world use different standard treatments now.
A second study in the same issue of the journal found that intensive control of blood pressure using an ACE inhibitor improved kidney function in children aged 3 to 18 with chronic kidney disease.
Even though the decrease in blood pressure was considered "modest," the authors stated that "the progression of renal disease was significantly delayed."
More information
The U.S. National Institute of Diabetes and Digestive and Kidney Diseases has more on dialysis.
