A study of 144 kidney transplants found that at least a year after surgery, success rates were comparable, regardless of the age of the donors or recipients. The results were reported today at a meeting of the Central Surgical Association in Tucson, Ariz.
"You can no longer make the argument that transplanting a kidney into an older recipient is a wasted organ," said Robert Stratta, M.D., director of Transplantation Services at Wake Forest Baptist.
About 50 percent of the more than 60,000 people on the waiting list for kidney transplants are age 50 or older. Wake Forest Baptist and other centers are grappling with how to best use the limited number of kidneys that are available each year from deceased donors.
"There is a critical shortage of kidneys for transplantation, which puts us in the difficult situation of rationing organs," said Stratta. "Some physicians have ethical concerns that providing elderly patients with scarce donated kidneys may not represent a worthwhile investment."
Stratta's research, however, found that by using newer methods to match the kidney with the recipient, the ages of the donors and recipients did not affect either patient survival or short-term survival of the transplanted kidney. This means both that more organs previously considered unusable might be transplanted and that older patients might be better candidates to donate and receive available organs.
From October 2001 through February 2004, Wake Forest Baptist transplanted 144 kidneys from deceased donors and found that a minimum of one year after surgery, transplant patients who were over age 60 did as well as younger patients, despite the fact that they usually received kidneys from older donors. Stratta had previously reported on success rates in 129 of these patients after six months and will continue to follow them long-term.
"We no longer consider chronological age to be a contraindication to either organ donation or organ transplantation," Stratta said.
Of the 144 transplants, about one out of four (26 percent) were in patients age 60 and older. The mean age of this group was 65, and seven kidney recipients were older than 70. Most of the patients (62 percent) in the older group received kidneys from older donors that once would have been discarded.
In comparison, the mean age for the younger patients was 46, and only 32 percent received kidneys from older donors.
At least one year after transplant, survival rates for the transplanted kidneys were 86 percent in the older group of recipients and 87 percent in the younger group. Patient survival was 92 percent in the older patients and 98 percent in the younger group.
Stratta said a key to success is using newer methods to match donated kidneys to recipients. In the past, kidneys were matched exclusively by blood and tissue type. Newer approaches to matching have come about as a result of a system implemented by the United Network for Organ Sharing (UNOS) in October 2002 for allocating higher-risk kidneys that were once considered unsuitable for transplantation and discarded.
These include kidneys from deceased donors over age 60 or those over age 50 with health conditions such as high blood pressure or elevated levels of a protein called creatinine. Levels of creatinine, which is produced by muscle, are used to determine kidney function.
Using kidneys from these donors, which UNOS calls expanded criteria donors (ECDs), permits more patients to benefit from transplantation, Stratta said, but requires careful matching. Wake Forest Baptist has doubled its number of transplants using ECD kidneys.
"We are matching based on age, weight and kidney function," said Stratta. "An older kidney has less capacity, and someone who weighs less doesn't need as much capacity. It is a concept that is in evolution."
Stratta believes that with careful patient selection, the kidneys from expanded criteria donors may function for as long as kidneys donated under the standard criteria, about eight to 12 years. He cautions, though, that "long-term follow-up is needed to ultimately determine the risks and benefits of kidney transplantation in this setting."