State policies meant to encourage people throughout the U.S. to donate organs over the past few decades have been largely ineffective, a new study suggests.

Creating a state fund to promote organ donations was the only policy linked to any increase in transplants, the researchers reported June 1 in JAMA Internal Medicine.

"We really need new strategies to bridge the gap between the organ need in the U.S. and the actual supply that we have," said Dr. Paula Chatterjee, the study's lead author from Brigham and Women's Hospital in Boston.

As of today, there are more than 123,000 patients on organ transplant waiting lists in the U.S., according to data from the Organ Procurement and Transplantation Network (OPTN).

On average, according to the OPTN, 21 people in the U.S. die each day while waiting for a transplant.

For the new study, the researchers looked at several types of state policies implemented from 1988 through 2010 meant to increase organ donations from living or deceased donors.

Those policies include public education programs, time off from jobs for donors, donor registries, tax benefits for donors and revenue pools to promote organ donation.

The researchers then compared states that did and didn't enact each kind of policy.

During the study period, the number of states adopting at least one donation policy rose from seven in 1988 to 50 in 2010, when six states had - by that point - adopted all policies.

Organ donations also increased from 5,909 in 1988 to 14,504 in 2010, the authors say, as did the number of transplants.

Overall, creating a revenue pool to promote donations was tied to about a 5% increase in transplantations, largely due to more organs from deceased donors.

"To really understand what makes it modestly successful, we do need more local or more granular data," Chatterjee told Reuters Health.

There was no increase in donations tied to any of the other policies, however.

"Unfortunately, the strategies haven’t been effective," Chatterjee said.

She and her colleagues caution that their study did have limitations, including that varying degrees of state implementation of policies may affect the results.

Data on how local communities implement policies will allow them to see which strategies are most effective, Chatterjee said.

In a companion paper in JAMA Internal Medicine June 1, Dr. Lynne Warner Stevenson highlighted an issue specific to patients on the waiting list for a new heart.

"I’ve been taking care of patients before and after heart transplants for about 30 years, and I’ve been realizing that my patients are waiting longer and longer," said Stevenson, director of the heart failure program at Brigham and Women's Hospital.

In her paper, she says the number of heart transplants in the U.S. in 2014 was about equal to the number in 1994 - but the number of people on the waiting list has increased.

This year, she said about 7,000 people will be listed for a heart transplant, but only about 2,200 hearts will be available.

"We really are overselling transplants, and that’s irresponsible for us," she told Reuters Health.

Stevenson suggests working to reduce new listings for heart transplants to balance the waiting list. That will take cooperation from people involved in the waiting lists, but also for the broader physician community.

In an editorial, Drs. Sally Satel and David C. Cronin II say it's time for a disruptive innovation.

Satel of the American Enterprise Institute in Washington, D.C., and Cronin of the Medical College of Wisconsin in Milwaukee suggest testing methods of rewarding people for donating organs.

"We’ve crossed that line – productively so – years ago," Satel said. "We pay for cadavers . . . Then of course there are sperm and eggs."

Instead of a lump sum of cash that would create a free market of organs, they suggest delayed payments such as in-kind rewards like a donation to a retirement fund, income tax credit or a tuition voucher.

"The non immediacy of it is arguably a benefit," Satel said.

"You don’t want people acting impulsively. That’s why building in a time lag could be advantageous and allay anxiety," she said.

She also said surveys show that the average person is very open-minded when it comes to rewarding people for their donations.

Chatterjee suggested waiting to see local data on policies before alternatives like the rewards are considered.