The shorter the waiting time at a transplant center, the longer patients are likely to live. A combination of center-related factors could mean up to a four-year difference in life expectancy for candidates.
The UF study is the first to analyze overall survival chances for people waiting for a kidney transplant, rather than for people who had already received a transplant.
"Patients want to know their survival long term, not just if they happen to make it to surgery," said lead researcher Jesse Schold, Ph.D., of UF's College of Medicine.
The findings are published in the February issue of the journal Medical Care.
"This is an important paper because it draws attention to an often ignored but critical aspect of transplantation — what happens to patients while they are waiting for a transplant," said J. Michael Cecka, Ph.D., of the University of California, Los Angeles, whose group first described in the 1970s the so-called "center effect," in which a patient's prognosis depends on the center where the transplant was done. Cecka was not involved in the current research.
"Unfortunately, not every patient who would benefit from a kidney transplant will ever get one — in fact, most of those patients will not get a transplant because there are not enough organs available for transplantation," he said.
Kidney transplantation doubles life expectancy compared with dialysis treatment. On average, wait time nationally for a deceased-donor kidney is four to five years, but in some states it is more than seven.
In 2007, at least 70,000 patients were on waiting lists for kidney transplants at one of 240 centers around the country, according to the Organ Procurement and Transplantation Network. Patients are prioritized by blood type, immune system activity and other factors. The longer a person waits, the more dialysis he or she gets, and the poorer the life expectancy.
Long waiting times for donor organs have led many people to seek alternatives, some of which have raised ethics questions. One example in the United States is a members-only organ-sharing "club" in which people who pledge to donate organs get preferred access to donations from other members. Internationally, there have been reports of people buying organs from live donors.
The UF research evaluated data from 1995 to 2000 on almost 109,000 patients from a national transplant database, using characteristics thought to have the greatest impact on patient survival: waiting time, past performance of a center in terms of patient death rates, proportion of non-ideal donors and number of deceased-donor transplants a center does a year.
Waiting time had the strongest effect on survival once a patient got on a transplant list. At centers with the longest wait times, patients' risk of death was a third higher than at those with the shortest waits.
Centers that had the highest proportions of donors considered high-risk because of age, cause of death, history of hypertension, or certain clinical measurements, had a slight elevation in death rates.
Past center performance, in terms of historical death rates, also had a slight positive effect on survival.
Contrary to expectations, the number of transplants a center does a year was not associated with patient survival. In general, high-volume centers are thought to have greater expertise, resources and facilities. But that seems a less important consideration for people who are still waiting to receive an organ.
"Maybe it does have some degree of benefit if you do reach the transplant episode, but many candidates don't," Schold said.
Waiting times and other information about transplant centers are available online from the Scientific Registry of Transplant Recipients and the U.S. Renal Data System.
Still, many patients might not feel that they have a choice — they go where their physician or insurer tells them to, or to the center closest to home.
"Patients should ask the question 'how likely am I to get a kidney at this center?'" said Robert Gaston, M.D., head of transplant nephrology at the University of Alabama, who was not involved in the study. "I think it's reasonable to ask that of their doctor, their insurance company and the transplant center they're referred to."
But whether patients have much choice in selecting a transplant center may be less important than just raising the issue of whether listing preferences and practices at different centers might need scrutiny, UCLA's Cecka said.
Just as his identification in the 1970s of the "center effect" on transplantation outcomes sparked interest in reducing skill differences among centers, this newly described "center effect" on candidate survival might invite a look at how to improve wait-listed patients' chances by addressing center variations.
Experts caution that center factors change over time, and that what might be the best place to go in a given year might not be the following year.
"Personnel and practices change — it's not a static picture," Gaston said.
Czerne M. Reid | EurekAlert!
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