Healthy older people are at relatively low risk of developing kidney failure during their lifetimes – even if they have somewhat reduced kidney function or higher than optimal blood pressure – making them good candidates to be living kidney donors, new research led by the Johns Hopkins Bloomberg School of Public Health suggests.
Despite excellent outcomes in those who have received kidney transplants from older donors, fewer than three percent of live kidney donors in the United States in 2014 were 65 years or older.
Researchers from the Chronic Kidney Disease Prognosis Consortium, reporting Nov. 6 in the New England Journal of Medicine, developed an online risk assessment to help evaluate, counsel and approve living kidney donor candidates. Instead of looking at a single risk factor, the tool analyzes the combined effect of 10 routinely available demographic and health characteristics to estimate the chance of developing kidney failure over the following 15 years and the remainder of a person’s lifetime. Currently, the criteria used to determine whether to approve a donor generally employs one health characteristic at a time.
While kidney donation likely increases the risk of developing kidney failure – donors are left with one kidney instead of two – it is hard to predict by how much. The new tool quantifies overall risk before donation, letting physicians know which potential organ donors are more at risk of developing kidney problems – even if they do not donate.
“Use of this online tool during the evaluation process gives decision makers the evidence to help them decide who can most safely donate a kidney for transplant,” says study author Morgan E. Grams, MD, PhD, a nephrologist and assistant professor of epidemiology at the Bloomberg School. “This assessment could minimize the number of living kidney donors who go on to develop kidney failure, support donation among people who were previously believed to be poor candidates and enhance informed consent and decision-making with potential donors.”
“Our ultimate goal is to develop a tool where we can sit down with a potential kidney donor and say: this is your risk if you don’t donate, and this would be your risk if you do donate, so you can decide if you feel the risk is too high,” says Dorry L. Segev, MD, PhD, a Johns Hopkins transplant surgeon also involved in the research.
While some healthy older people may make good donors, the online tool suggests that younger people – who are expected to live longer with a single kidney – are at much greater risk of developing kidney failure during their lifetime, as are African Americans. Grams, who is also an assistant professor at the Johns Hopkins University School of Medicine, says transplant doctors should use caution when approving young donors, particularly those who are obese, a group that is also at increased risk.
The tool can be found at www.transplantmodels.com/esrdrisk.
For the study, the researchers looked at data from nearly five million Americans who participated in seven large studies to project the long-term incidence of kidney failure in people with two kidneys. Using this very large data set, they were able to determine how 10 routinely available demographic and health characteristics including age, race, gender, hypertension, smoking and obesity work together to predict future kidney failure.
To determine 15-year and lifetime risk, you can go to the website and choose fields such as race, age, smoking status, body mass index (BMI) and more. The calculator then reveals your chance of developing kidney failure over a lifetime. If risk is low enough, you may be an acceptable candidate for kidney donation with the assumption that your remaining kidney will be strong enough to keep you healthy.
According to the United Network for Organ Sharing, there were 122,662 people waiting for kidney transplants in the United States as of Oct. 31. Last year, 17,105 kidney transplants took place in the U.S., 5,538 of them involving organs from living donors.
“Kidney Failure Risk Projection for the Living Kidney Donor Candidate” was written by Morgan E. Grams, MD, PhD; Yingying Sang, MS; Andrew S. Levey, MD; Kunihiro Matsushita, MD, PhD; Shoshana Ballew, PhD; Alex R. Chang, MD; Eric K.H. Chow, MSc; Bertram L. Kasiske, MD; Csaba P. Kovesdy, MD; Girish N. Nadkarni, MD, MPH; Varda Shalev, MD, MPA; Dorry L. Segev, MD, PhD; Josef Coresh, MD, PHD; Krista L. Lentine, MD, PhD; Amit X. Garg, MD, PhD.
The research was funded by grants from the National Institute of Diabetes and Digestive and Kidney Diseases (K08DK092287 and R01DK096008). The Chronic Kidney Disease Prognosis Consortium Data Coordinating Center is funded in part by a program grant from the U.S. National Kidney Foundation (NKF funding sources include AbbVie and Amgen) and the NIDDK (R01DK100446-01).
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