Researchers at PennMedicine are piling on. They’re the latest to add a critique to the scoring system that ranks patients waiting for a liver transplant.
“Like any kind of mathematical score it’s not perfect,” said David Goldberg, lead author of the new study. “Our paper along with others is helping to spur these discussions.”
Donor livers are scarce, and the national waiting list for a transplant is 17,000 people long.
The transplant allocation system uses something called a MELD score — Model for End Stage Liver Disease — to determine which patients should be first in line for an organ.
The higher your score, the higher your risk of dying while you wait for a liver.
“We call it an urgency-based model, or sickest first,” said Goldberg, an instructor of Medicine at the Perelman School of Medicine of the University of Pennsylvania.
Goldberg and colleagues reviewed national data to understand the “exception points” given to patients with the lung condition hepatopulmonary syndrome, which drives down oxygen levels in the blood.
“Maybe we were giving patients more priority than they needed? Maybe they were getting too much priority?” Goldberg said.
Right now, all patients with HPS get the same number of those exception points. The Penn study suggests that higher priority should, perhaps, be reserved for a subset of sicker patients who have the lowest blood-oxygen levels.
Most professionals in the transplant community agree that patients with HPS do need a transplant quicker — and that they should get some kind of increased priority.
“The question was how much, and that’s what we were trying to answer,” Goldberg said.
‘A difficult premise’
Liver doctor Ryutaro Hirose said the PennMedicine study is the latest in a string of research scrutinizing the MELD score.
Hirose is vice chair of the Liver Transplantation Committee for the United Network for Organ Sharing, which manages the nation’s transplant system.
“To say that one group of patients is more deserving than another is a difficult premise, however we can try to model who is going to die first,” Hirose said.
Since the MELD score was established in 2002, the transplant community has three times made adjustments to the exception points it doles out.
New data is always coming in, and Hirose says his colleagues in the field have new ideas all the time about tweaking the system. Sometimes, it’s to prevent disparities in health care; other times, it’s to save a greater number of lives; and, often. there are debates about fairness from region to region of the country.
“When a person goes to a certain area of the country that has a relative abundance of livers — relative to how many sick patients there are — people can get transplanted very quickly in those areas,” Hirose said. “Whereas in San Francisco and Philadelphia, you have to have usually a much higher MELD score to get hope of access to a transplant.”
“We have to vet the ideas among all the people in the country, as well as do studies and statistical modeling, to see what the effects may be of each policy change — and then we send it out for public comment,” Hirose said. “It’s a little bit like the U.S. Congress. You have to get to some form of consensus, which is sometimes very difficult to achieve.”
Goldberg both studies the transplant system and cares for individual patients.
His new study puts him in the sticky position of questioning a system that gives some of his patients “extra” points
“For my individual patients, it’s a good thing, because it allows them to get a transplant, but maybe it’s not so good for the entire transplant community,” he said.