(CNN) As the opioid epidemic has skyrocketed in the United States, a rise in the number of drug overdose deaths has contributed to a rise in organ transplants, made possible by overdose-death donors, across the country.

A study published in the journal Annals of Internal Medicine on Monday now reveals just how much of an increase there has been in the number of overdose-death donors, from being only 1.1% of all donors in 2000 to 13.4% in 2017.

The study suggests that a rise in organ donations from drug overdose deaths could help America's organ shortage -- but it also shows that between 2000 and 2017, many organs from overdose-death donors were not used to save lives when they could have been.

"The current epidemic of deaths from overdose is a tragedy. It would also be tragic to continue to underutilize life-saving transplants from donors," said Dr. Christine Durand, assistant professor of medicine and oncology at Johns Hopkins University, who led the study.

"We have an obligation to optimize the use of all organs donated. The donors, families and patients waiting deserve our best effort to use every gift of life we can," she said.

Durand added that there are no regulations specifically pertaining to transplanting organs from overdose death that could limit those organs from being used, but there are regulations related to donors at "increased risk" for transmitting certain viruses through organ transplantation.

"In our study, 56% of overdose-death donors were labeled as increased infectious risk donors. These donors require specialized testing for HIV and hepatitis as well as specialized consent for the transplant recipient. There is stigma related to this 'increased infectious risk' label," Durand said.

"In reality, the 'increased risk' of HIV or hepatitis in these donors is very low," she said.

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As of Monday afternoon, about 114,746 people in the United States were in need of a lifesaving organ transplant, but between January and March, there were only 4,109 organ donors, according to the federal Organ Procurement & Transplantation Network

Those numbers reveal a huge gap between supply and demand.

"For people waiting on an organ transplant right now, I would like to think that our studies bring them hope that they could receive a transplant and have more donors that could help them," Durand said.

"I also don't want to lose sight of the people who made these transplants possible: the donors and their families," she said. "In a time of greatest tragedy, they made a powerful decision to save the lives of people waiting on a transplant. That means they are generous, compassionate people. They are people I admire. They are the people who make organ donation and transplantation possible."

'Many organs donated after overdose death were discarded'

The study involved data from the Scientific Registry of Transplant Recipients , which included information on donors, wait-listed candidates and transplant recipients between January 2000 and September 2017.

The researchers identified 7,313 overdose-death donors in the data who had at least one organ recovered during that time. There were 19,897 transplants from those donors. The data showed that the number of overdose-death donors increased by 17% per year between 2000 and 2017.

In comparison, over that time, the number of trauma-death donors increased by 1.6% per year, and the number of medical-death donors increased by 2.3% per year.

A trauma-death donor could be someone who died by drowning, gunshot or asphyxiation, among other causes. A medical-death donor could be someone who died by hemorrhage, stroke or heart attack, among other causes.

In particular, the researchers found that the number of overdose-death donors climbed from 66 in 2000, encompassing 1.1% of the national pool, to 1,263 in 2016, encompassing 12.7%, and then to 915 in the first nine months of 2017, encompassing 13.4%.

The researchers also found that in 2016, overdose-death donors accounted for at least 10% of donors in 29 states, with the highest percentages seen in Massachusetts at 35.6%, New Hampshire at 32.4%, New Jersey at 25.7%, New York at 23.1% and Maryland at 22.7%.

Overall, the researchers found a 24-fold increase in overdose-death donor transplants, from 149 in 2000 to 3,533 in 2016.

"Patients who received transplants from these donors had excellent outcomes; patient survival and organ function were similar to cases when donors died due to trauma and similar or better than cases when the donor died due to medical causes of death, like heart attack or stroke," Durand said.

"What was somewhat surprising was that, despite the good outcomes we see in transplant recipients, many organs donated after overdose death were discarded -- that is, they were surgically recovered but then not used for transplant in any patient," she said.

During the course of the study, the researchers identified 1,665 kidneys, 501 livers, 117 hearts and 23 lungs from overdose-death donors that were recovered but discarded.

Those organs were discarded at a higher rate than those from trauma-death donors but lower than those from medical-death donors, the researchers found. For instance, kidneys were discarded at a rate of 14.1% among overdose-death donors, compared with 8.8% among trauma-death donors but 26.1% among medical-death donors.

"This discard was primarily related to an increasing prevalence of hepatitis C infection among overdose-death donors and increased infectious risk," Durand said. "With transplant, you always have to balance the risk and benefit," she said. "Patients and their transplant teams have to weigh the small risk of an infection like hepatitis C -- for which we now have a cure -- against the risk of dying on the wait list."

'We need to save more lives'

The study had some limitations, including that the researchers were unable to determine how many of the overdose-death donors died specifically of opioid drug overdoses versus non-opioid overdoses. Also, states and jurisdictions vary in their reporting of specific drugs implicated in overdose deaths.

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Dr. David Klassen, chief medical officer for the United Network for Organ Sharing , said in an email that he thought the new study was "interesting" and added insights into the effects of opioid epidemic-related deaths on organ donation, as well as the outcomes for transplant recipients.

"We at UNOS have witnessed the increase in the numbers of organ donors, especially over the past several years, resulting from the tragedy of the opioid crisis in the United States," said Klassen, who was not involved in the new study.

"The study importantly illustrates that recipient outcomes are similar to those obtained from donors who die from other causes. It also illustrates how the transplant system has successfully incorporated the use of organs from these donors into clinical practice, resulting in benefits to many patients," Klassen said.

"Underutilization of organs from these donors still occurs and is probably underestimated in this paper by looking at 'discard rates' since this does not account for organs that are never procured despite the possibility of providing benefit to potential recipients," he said.

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Dr. Camille Nelson Kotton, clinical director of transplant and immunocompromised host infectious diseases at Massachusetts General Hospital, wrote an editorial accompanying the new study.

The editorial calls for enhanced efforts to provide organs for patients most likely to have long-term benefit from transplantation.

"We need to save more lives of persons awaiting organ transplant," she wrote. "The transplant community should understand these new data and forge ahead toward better transplant outcomes for more recipients."