Research News

A team of Cleveland Clinic physicians and researchers have developed an improved method to prioritize individuals on the lung transplant waiting list, with the potential to improve long-term health outcomes for patients. 

The results were published in the American Journal of Respiratory and Critical Care Medicine. 

Being put on the organ transplant waiting list does not guarantee a specific "place in line." Patients on the list are mathematically scored based on several qualities that balance how stable they are while waiting, their chances of survival after receiving a new organ and how easily they can be matched to available organs. Patients with the highest scores are given priority and offered donor lungs first. 

The U.S. transplant system scores patients on the list based on a series of tests that are administered twice a year by their transplant centers. This schedule means that unless a patient's health suddenly and drastically changes, their score will remain the same for at least six months. The problem with this method, says Maryam Valapour, MD, MPP, is that the scoring equations fail to consider how a patients' health status changes as they spent time on the list.

"The longer a patient lives with a severe lung disease, the more their risk of developing severe complications increases," says Dr. Valapour. "This is something clinicians observe every day - that our patients' risk of developing complications changes over time." These changes are different for each patient, depending on the type and severity of their diagnosis and the patients' own characteristics. 

"In other words, some patients' scores may not reflect how urgently they need a transplant," she says. 

Dr. Valapour, Director of Lung Transplant Outcomes at the Respiratory Institute and Jarrod Dalton, PhD, Director of Lerner Research Institute's Center for Populations and Health Research led the project with the goal of improving the scoring equations and better determining who could or could not wait for an organ. The research team also included Carli Lehr, MD, PhD, Belinda Udeh, PhD and Paul Gunsalus, MS, from Cleveland Clinic as well as Johnie Rose, MD, PhD from Case Western Reserve University. 

The team analyzed over 12,000 lung transplant candidates who were awaiting transplant and who had been on the waiting list between 2015-2020. They used the data to determine how the amount of time a patient spent on the waitlist affected their clinical outcomes and showed that, for some transplant candidates, their risk of death prior to transplant increased as they spent longer times waiting for an organ. 

When the team looked at patients who had died on the waiting list, they found that many had been given low priority scores and were considered "stable" at some point within six months of their death. Re-calculating those original scores with their new equation consistently marked those patients as high priority. Meanwhile, using the new equation on patients who originally received low-priority scores and remained stable over time did not result in any difference in score. 

"The approaches we present in our paper are capable of identifying whose trajectory is more stable on the waiting list versus those whose trajectory is worsening between six-month clinical updates," says Dr. Dalton, who is first author of the paper. 

James P. Kiley, PhD, Director of the Division of Lung Diseases at the National Heart, Lung and Blood Institute (NHLBI), says the team's new equations have the potential to greatly improve patient care.

"This research advances us towards development of a more comprehensive prediction model for risk of mortality among lung transplant candidates," Dr. Kiley says. "This could help guide decisions about patients who are in greater need for lung transplant and increase their odds for survival."