In 2022, more than 71,000 people were on the U.S. kidney transplant waiting list and more than half of those listed had been waiting at least five years. Yet despite this urgent demand, about one in four kidneys recovered from deceased donors goes unused, a share that has climbed steadily in recent years—from 5.1% in 1988 to 24.6% in 2021.

A new study from the University of Minnesota School of Public Health (SPH) examined the country’s kidney donation system and found that many donated kidneys considered to be of “acceptable quality” are never used. Kidneys classified as “acceptable” which are often discarded in the U.S. typically come from donors who score lower on a range of clinical and demographic measures, such as older age at death, obesity, hypertension, diabetes, and other health factors. Rather than discarding them, the study notes that many of these acceptable kidneys could help thousands of older adults with kidney failure to live longer, healthier lives.

To conduct the study, researchers created a simulated model of adults aged 65 or older who were on the kidney transplant waiting list. The researchers tracked this simulated population of 100,000 people, following their potential waiting list and post-transplant outcomes over the remainder of their lifetimes. Then, researchers tested what would happen if transplant centers increased the rate of transplantation by between 5% and 25% compared with current practices using  acceptable-quality donor kidneys.

The study, published in JAMA Network Open, found:

• More transplants led to fewer deaths. Increasing the use of acceptable-quality kidneys by 25% was linked to about 141 fewer deaths per 10,000 people on the transplant waiting list.
• Better health at a reasonable cost. Increasing the use of acceptable-quality kidneys improved both the length and quality of life for older patients. At a cost of about $8,100 for each additional quality-adjusted life year  gained, the policy produced extra years of healthy life at a very low cost compared with most health interventions.
• Potential overall cost savings. When researchers included the time patients and caregivers spend receiving and providing care, the strategy not only improved health but also saved about $10,200 per patient on average.

“Too many kidneys that could help patients are going unused,” said lead author and SPH researcher Matthew Kaufmann. “At a time when tens of thousands of Americans are waiting for a kidney transplant—and many older patients grow sicker or die before an organ becomes available—our findings suggest the U.S. transplant system may be missing opportunities to save lives. Policymakers and healthcare leaders should consider changes that make better use of acceptable-quality donor kidneys so older adults can receive transplants sooner, live longer, and enjoy better quality of life.”

The authors suggest policymakers and transplant leaders consider changes that make it easier for centers to use acceptable-quality kidneys, especially for older patients who may be willing to accept a slightly lower-quality organ in exchange for a shorter wait. This could include updating policies so transplant centers are not penalized for serving older or sicker patients, and strengthening shared decision-making so patient preferences, including a willingness to accept organs from medically complex donors, are made known.

The research was supported by a grant from the Agency for Healthcare Research and Quality.