THURSDAY, Jan. 16, 2020 (HealthDay News) -- Many of the donor kidneys that are discarded each year in the United States could instead be effectively transplanted, a large new study suggests.

At issue are kidneys from deceased donors that are acutely injured. Right now in the United States, about 30% of those organs are discarded, rather than being given to patients on transplant waitlists.

But the new study found that donor kidneys with signs of acute injury were no more likely to fail than non-injured kidneys from similar donors.

The findings, recently published online in JAMA Network Open, are based on more than 25,000 U.S. patients who received donor kidneys between 2010 and 2013.

"This is the strongest piece of evidence to date that these [acutely injured] kidneys do just fine," said senior researcher Dr. Chirag Parikh, director of nephrology at Johns Hopkins University School of Medicine, in Baltimore.

"Acute injury" may sound like an ominous problem. But in the context of organ donation, it is usually a manageable issue, Parikh said.

Often, deceased donors are relatively young people who were treated in the intensive care unit for severe injuries. Their kidney function may be abruptly compromised by, for example, a severe drop in blood pressure or medications used in their care.

"For the most part, it's reversible, which is why these kidneys do well after transplantation," Parikh said.

In the United States, nonprofit organ procurement organizations are responsible for evaluating potential donors and coordinating the donation process for a given geographical area. Transplant centers within that area can accept or decline an organ offer, and each hospital has its own criteria when it comes to less-than-perfect donor organs.

There can be a concern that an acute injury will compromise the "lifespan" of a donor kidney, Parikh said, so transplant centers may "play it safe" and wait for a seemingly better offer.

It's part of a broader "cognitive bias" that it is better to hold out for a higher-quality kidney, agreed Dr. Sumit Mohan, a kidney specialist and associate professor of medicine at Columbia University in New York City.

Ideally, surgeons want to transplant kidneys that will start working right away, said Mohan, who was not involved in the study. An acutely injured kidney generally needs a few days to recover -- and surgeons may balk at that.

"But even though these kidneys take a few days to wake up, they end up doing well," Mohan said.

He called the new findings "important," as they show that more of the available donor kidneys in the United States could be successfully used.

"We should be better managing the organ supply we have," Mohan said.

Nearly 95,000 Americans are on the waitlist for a donor kidney, according to the United Network for Organ Sharing (UNOS), the nonprofit that manages the nation's donor organ system. Each year, around 9,000 of those patients either die or are removed from the waitlist because of deteriorating health.

That is not merely because of an organ shortage. In a study published last year, Mohan found that U.S. patients who died waiting for a kidney actually had multiple offers of a donor organ -- but their transplant center turned them down.

In fact, half of those patients had more than 16 donor kidneys offered, and declined, before their deaths.

"I think transplant surgeons are trying to do the right thing," Mohan said. But, he added, they may also be "misjudging" the odds of getting a more-ideal kidney in time.

Darren Stewart, a research scientist with UNOS, said, "There probably is an underutilization of these [acutely injured] organs."

Stewart pointed to some of the steps UNOS is taking to improve the use of available donor kidneys. One is a new pilot program called the Kidney Accelerated Placement Project; it aims to more efficiently get "difficult-to-place" kidneys to transplant centers that have a history of using them.

Biopsies of the donor organ might help in some cases, too, he said. In a recent study, Stewart's team found that, in hypothetical scenarios, surgeons were much more willing to accept an acutely injured kidney if it were accompanied by reassuring biopsy results.

The current study focused on U.S. patients who received kidneys from 13,444 deceased donors. Half of the donor organs included in the study had acute injuries, the other half did not. But the donors were otherwise similar, in terms of age, race, overall health before death, and other factors.

It turned out that acutely injured kidneys were no more likely to fail over the next five years than non-injured organs. Overall, the donor organs stopped functioning at a rate of roughly 3% per year, in both groups.

As for what patients can do, Stewart recommended having "open conversations" with your surgeon when you are first placed on the waitlist, and then periodically afterward. Discuss the benefits and risks of a transplant with a less-than-ideal kidney, versus staying on dialysis, and what you want as far as quality of life -- which, Stewart noted, will likely improve with a transplant.

"This isn't only about survival," he said. "It's about quality of life, too."

More information

For more on organ transplantation, visit the United Network for Organ Sharing.