Lead author Dr. Brie Williams, assistant professor of medicine in the division of geriatrics at the University of California, San Francisco, says the number of applications annually for compassionate release is unknown because many prisoners die during the laborious review process, which can take months -- even years.
There were 27 such releases from federal prisons in 2008, compared to 399 deaths occurring behind bars.
"Current compassionate release guidelines are failing to identify seriously ill prisoners who no longer pose a threat to society, placing huge financial burdens on state budgets and contributing to the national crisis of prison overcrowding," Williams says in a statement.
The study authors call for the development of standardized national guidelines by an independent advisory panel of palliative medicine, geriatrics and correctional healthcare experts.
To be released from federal incarceration, a prisoner must establish "extraordinary and compelling" reasons, but the researchers say prisoners must have a terminal prognosis and be expected to die quickly, but it is difficult to predict when death might occur.
The result is a so-called Catch 22 -- if compassionate release is requested too late, prisoners die before their application is complete and if requested too early, terminally ill prisoners may live longer than expected "and perhaps pose a threat to society," the researchers say.
The findings are published in the Annals of Internal Medicine.