SOURCES: Anthony Bleyer, M.D., professor of medicine, and nephrologist, Wake Forest School of Medicine, Winston-Salem, N.C.; Leslie Spry, M.D., spokesperson, National Kidney Foundation, and nephrologist, Lincoln, Neb.; Stephen Rayhill, M.D., professor of surgery, and director of transplant clinical services, University of Washington, Seattle; Nov. 14, 2014, presentation, American Society of Nephrology annual meeting, Philadelphia
FRIDAY, Nov. 14, 2014 (HealthDay News) -- Even if they were willing, most people in the United States aren't qualified to be kidney donors because of health or financial reasons, a new study has found.
More than 75 percent of the population could not donate, said Dr. Anthony Bleyer, a nephrologist at Wake Forest School of Medicine, who led the study. It is to be presented Friday at the American Society of Nephrology meeting in Philadelphia.
While the national kidney shortage has been well-documented, Bleyer noted, to his knowledge, there have been no population-based studies to look at the potential donor pool.
According to the National Kidney Foundation, about 100,000 people in the United States are now waiting for a kidney transplant. In 2013, there were almost 17,000 kidney transplants, including almost 6,000 from living donors.
To determine what percent of the U.S. population would qualify as donors, Bleyer said, "we modeled it after what a transplant center would take."
He used the National Health and Nutrition Examination Survey (NHANES), a large survey of people between 21 and 70 years old, and looked at health conditions to calculate how many would be eligible donors.
Among those disqualified were those who were obese, those who were excessive drinkers (more than four drinks a day), and those with diabetes, skin cancer, high blood pressure, HIV, coronary artery disease or congestive heart failure.
Bleyer then disqualified those with an annual family income of less than $25,000, the U.S. poverty level, reasoning they could not afford to miss work for the two to three weeks required for recovery after donation. And he ruled out non-U.S. citizens, reasoning that their follow-up care could not be assured.
His findings showed that, based on preventable health conditions, 55 percent could not donate. Adding in low-income and non-citizens increased the percentage to more than 68. And when he excluded smokers and those with shortness of breath walking up an incline (figuring they were not in good health), it rose to more than 75 percent.
"I think the take-home message is, as a population, the healthier we are, the better we would be able to deal with many health problems, and the more donors there would be," Bleyer said.
A spokesperson for the National Kidney Foundation who reviewed the findings pointed out that the study does have one limitation.
"They are looking at people from 21 to 70," said Dr. Leslie Spry, who is also a nephrologist in Lincoln, Neb. Most of the best donors are ages 21 to 55, he noted, and if the researchers had focused on that smaller age group, the percent of qualified donors would surely increase.
"It is a good, thought-provoking study," said Dr. Stephen Rayhill, director of transplant clinical services at the University of Washington, adding that the findings did not surprise him.
However, he noted, as the population gets less healthy, fewer are eligible as donors. But that also means more of those people may end up on the recipient list.
Rayhill also noted that more than half of all kidney transplants are a result of blood pressure problems or diabetes.
Research presented at scientific meetings should be viewed as preliminary until published in a peer-reviewed medical journal.
To learn more about kidney disease and how to stay healthier, visit National Kidney Foundation.