Biggest study of its kind finds no health downside to donation
WEDNESDAY, Jan. 28 (HealthDay News) -- Americans who give the gift of life by donating a kidney tend to lead long, healthy lives themselves.
That's the conclusion of the largest, longest follow-up of donors ever conducted.
"Their lifespan is comparable to others of the same age, gender and ethnic background," said study author Dr. Hassan N. Ibrahim, an associate professor of medicine at the University of Minnesota. "Indeed, it appears that that kidney donors might actually have better survival."
Ibrahim and his colleagues reported their findings in the Jan. 29 issue of the New England Journal of Medicine.
The study tracked outcomes for nearly 3,700 people who donated kidneys, some as far back as 1963. It found that "their quality of life was better than 60 percent of the people in the general population of the same age and gender," Ibrahim said.
This is the first U.S. study to compare the survival of kidney donors to that of the general public, he noted. Two previous, smaller studies done in Norway and Sweden found similar results, but they did not measure the health of donors in as much detail or for as long as in this study, he added.
In addition to overall health, the study looked at measures of kidney function such as the glomerular filtration rate (the flow of filtered fluid through the kidney) as well as the presence of conditions such as high blood pressure.
"Kidney donors have excellent glomerular filtration rates 85 percent of the time," Ibrahim said. "Kidney donors are not likely to develop high blood pressure or have protein in their urine."
End-stage kidney failure developed in only 11 of the thousands of donors over the years, the study found.
Still, these results cannot necessarily be extrapolated into the future, Ibrahim said, because with more than 100,000 Americans on the waiting list for kidney transplants and the limited number of kidneys available from deceased donors, there is pressure to loosen the criteria for living donors. The ideal donor is a healthy young person with normal blood pressure.
"It is clear that the excellent results seen here reflect very strict criteria," Ibrahim said. "Transplant centers now are willing to consider older donors and people with mild hypertension." That could mean that in decades to come the outcomes for these less-healthy donors "might look different," he said.
It might indeed, because "the average age of living donors continues to increase," noted Dr. Jane Tan, an assistant professor of medicine at Stanford University and co-author of an accompanying editorial.
"Many of the patients I see have been waiting for seven years," Tan said. "Spouses want to donate, people in their 60s. We don't know what the consequences will be."
And the newly reported study was done in a primarily white population, which is also a potential limitation on its findings, Tan said. "About 12 percent of kidney donors are African-Americans," she said.
A study now being started could fill in that gap, Ibrahim said. Performed in collaboration with the Mayo Clinic and the University of Alabama, the study will include more than 8,000 kidney donors, many of them blacks. "We hope to have results in two to three years," he said.
A balance of possible benefits and dangers must be made when considering less-than-ideal donors, Ibrahim said. "Take a 65-year-old donor with mild hypertension," he said. "There might be less severe consequences than for a 20-year-old with hypertension."
"The standards by which we screen kidney donors are quite rigorous right now," Tan said. "We believe it is safe, but we want to ensure that we have donor safety in mind."
Want to learn more about kidney donation? Head to the National Kidney Foundation.
SOURCES: Hassan N. Ibrahim, M.D., associate professor, medicine, University of Minnesota, Minneapolis; Jane Tan, M.D., assistant professor, medicine, Stanford University, Stanford, Calif.; Jan. 29, 2009, New England Journal of Medicine
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