NEW YORK - Donating a kidney doesn't appear to have any long-term health consequences for the donor, a reassuring study shows.
Researchers at the University of Minnesota found those who gave up one of their two kidneys lived a normal life span and were as healthy as people in the general population. The donation also didn't raise the risk of having kidney failure later.
Kidney donation generally has been considered safe, although with surgery, there always are risks. The new research of nearly 3,700 donors dating back more than four decades is the largest and longest study to look at long-term outcomes, said the researchers. They reported their findings in Thursday's New England Journal of Medicine.
"It is a confirmation that living donation is a safe thing," said Dr. Matthew Cooper, a transplant surgeon at the University of Maryland, who was not involved in the research.
Kidneys filter waste and excess fluid from the blood. If your kidneys fail, the options are dialysis or a transplant. More than 78,000 people are on the national waiting list to receive a kidney from a deceased donor. The need for kidneys has soared with the rise in diabetes and obesity, and the wait can last for years.
Living donation has increased as more people became willing to donate and newer surgery techniques shortened recovery time. In 2007, more than a third of the 16,629 kidneys transplanted in the U.S. came from living donors, according to the United Network for Organ Sharing.
Dr. Hassan Ibrahim, the study's leader, and his colleagues wanted to find out what happened to the 3,698 people who had donated a kidney at the university since 1963. They tried to contact everyone and used government records to find out who had died. A group of 255 donors was randomly selected to have kidney and other tests. Results were compared with health outcomes for the general population.
Overall, 268 of the donors died, which the researchers said was comparable to survival in the general population. Eleven donors developed kidney failure decades later and needed dialysis or a transplant. The researchers said the rate of kidney failure in the donors was lower than that reported in the general population.
Most of the donors tested had good kidney function and reported an excellent quality of life, the study found.
The good outcomes likely reflect the strict criteria used to pick the donors, the researchers said. The donors had to be healthy with no kidney problems, and be free of high blood pressure and diabetes - two main causes of kidney disease.
Ibrahim said he hopes the results will increase donations and encourage transplant centers to continue to carefully select donors and not relax their requirements.
"We think these donors do extremely well because they were screened very well," said Ibrahim.
While there are no regulations for selecting living donors, the transplant network offers guidelines, said Cooper, who heads a UNOS committee on living donors. He said any kidney donor who later needs a transplant is given priority on the waiting list.
"There is a recognition of the sacrifice that these people have made," Cooper said.
Drs. Jane Tan and Glenn Chertow, of Stanford University School of Medicine, who wrote an accompanying editorial in the journal, noted that the study donors were mostly white and were likely younger than donors today. The results may not apply to older, nonwhite donors, they said.
The value of the study is its large size and duration, Tan said.
"We always have to be careful when it comes to potential harm to another individual," she said. "This study is very reassuring."
The University of Minnesota is part of a similar, ongoing study with other transplant centers that will have a larger and more diverse donor group, Ibrahim said.
One of the study donors said she didn't worry about potential problems when she gave a kidney to her oldest brother in 1983.
"I really didn't think too much past that," said Susan Kivi, 52, of Roseville, Minn. "He just deserved another chance to live a normal life."
Kivi said her recovery from surgery was a little harder than expected. But she hasn't had any health problems related to giving up a kidney since then. Her brother died about four years later.
"It was worth it. He got a few good years," she said.