It has become increasingly clear that patients in the United States are starting dialysis at higher and higher levels of kidney function. A team of researchers, led by Dr. Ann O'Hare, University of Washington associate professor of medicine and affiliate investigator at Group Health Research Institute, set out recently to find out what this means for patients, and how much earlier patients are starting dialysis compared with past practices.
Researchers from Washington state and California found that over a ten-year period, from 1997 to 2007, patients are starting dialysis approximately five months earlier on average. The study, "Trends in timing of initiation of chronic dialysis in the United States," is published in the Archives of Internal Medicine. Changes in timing are not explained by changes in measured patient characteristics and most likely reflect a shift in dialysis initiation practices over this time period, researchers said.
Dialysis is an intensive, time-consuming and expensive procedure for patients, said O'Hare. "It's a substantial commitment, taking place three times a week, for three or four hours per treatment, and costing several hundred dollars per treatment. When you look at the overall chronic dialysis population, our findings are significant."
The research team estimated that the difference in timing translates into 63 additional hemodialysis treatments, 189 or more hours of treatment and approximately $14,490 in additional payments for dialysis for each patient, or more than $1.5 billion if extrapolated to patients in the study who initiated dialysis in 2007.
Researchers used two different data sources for the study: the United States Renal Data System, a national registry of end-stage renal disease and a detailed renal database from the Group Health Research Institute. The national registry contains details on the level of kidney function for patients starting dialysis. The Group Health data contain information on the rate of loss of kidney function prior to dialysis initiation not available in registry data.
O'Hare said the findings are also important in light of other recent research that found starting dialysis earlier did not improve a range of health outcomes. "Patients are starting chronic dialysis significantly earlier, but there is no real evidence that it is beneficial," she said.
Researchers said the findings call for more careful evaluation of current dialysis initiation practices in the U.S. "We really need to take a good critical look at what we're doing," said O'Hare. "Our study did not reveal the rationale for initiating chronic dialysis sooner, nor did it provide details on circumstances, signs and symptoms that might have prompted dialysis initiation . It's an open question as to why this is happening, but these findings provide a rationale for more detailed study to better understand practices and what's driving this trend."
In addition to O'Hare, researchers involved in the study include Drs. Ilan Zawadzki, Walter Clinton and Eric B. Larson of Group Health Cooperative and the Group Health Research Institute; Drs. Andy Choi and John Boscardin of the University of California San Francisco; Dr. Paul Hebert of the University of Washington and the VA Puget Sound Healthcare System; Dr. Leslie Taylor of the VA Puget Sound Healthcare System and Dr. Manjula Tamura of Stanford University and the VA Palo Alto Healthcare System. The study was funded by a Beeson Career Development award from the National Institute on Aging, U.S. National Institutes of Health, to Dr. O'Hare.
The study is dedicated to the memory of Dr. Choi, who made generous and important contributions to this work. Choi died unexpectedly during the final stages of manuscript preparation, leaving behind a wife and two young daughters. O'Hare described him as a "rising star" in his field.