For the roughly 6,000 people each year who give up a kidney to someone in need of a transplant in the United States, a new study finds that generosity may come at a price: a roughly tenfold increased risk of kidney failure in the 15 years following their donation.
That increased risk, however, tells only half the story – and not, depending on how you look at things, the more important half.
In the 15 years after he or she goes under the knife, a live kidney donor has a 0.3 percent likelihood of developing end-stage kidney disease requiring chronic dialysis or a transplant, researchers from Johns Hopkins University have found. While that is higher than the .04 percent probability he or she would have had as a nondonor, the fact is that kidney failure remains a highly improbable outcome.
The study, published in the Journal of the American Medical Association, is the first to assess the absolute risk a kidney donor faces after the operation and the added risk he or she incurs as a result of it. It comes at a time when the gap between those needing a kidney transplant and the availability of the organs is vast: About 93,000 Americans are awaiting an available kidney, and most will wait at least five years before a kidney from a deceased donor becomes available.
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Assessing the risk
Living donors – relatives, friends and increasingly strangers – are narrowing that gap. In 2011, 42.5 percent of kidney transplants came from living donors, with more than 31,000 such procedures performed in more than 100 countries. And while donors are told the loss of a kidney cannot be without risk, they haven’t had many hard facts to guide them in their decision. Now, they do.
“The extra risk they’re taking from donating a kidney was very low,” said Johns Hopkins University transplant surgeon Dorry L. Segev, who led researchers in reviewing the records of all 96,217 people who donated a kidney for transplantation in the United States between April 1994 and November 2011. “It’s actually very reassuring,” he added.
Crucial to this finding is the fact that kidney donors are not only unusually generous: They are also, as a group, unusually healthy. Compared with the U.S. population at large, they start with a much smaller risk of going on to develop kidney disease.
When you take their chance of developing end-stage kidney disease and multiply it by 10, Segev said, “the result is still a very low number.”
Dr. Gabriel Danovitch, who heads the University of California, Los Angeles’ kidney and pancreas transplant program and was not involved in the study, said that in roughly 30 years of performing kidney transplants, he has rarely seen donors who express regrets – even if they go on to develop kidney disease themselves. After “thousands and thousands” of transplants, Danovitch reckoned that he saw perhaps five donors who went on to need transplants.
“The halo effect of being a kidney donor is the gain these patients get for the finite, but real – and small – additional risk they take upon themselves,” he said.