Study analyzes left digit bias in organ donors entering a new decade of age

American transplant centers as well as organ procurement organizations, the groups responsible for recovering organs from deceased donors in the United States, were less likely to accept or select organs from donors who were 70 years old when they died compared to those who were 69, new research found.

This is an example of left digit bias, a common type of unconscious bias that involves placing value based on the first digit in a number and thus is often linked to ageism.

A previous study had revealed this type of bias is present when organizations decide whether or not to discard donor kidneys. Clare E. Jacobson, M.D., a general surgery resident at University of Michigan Health, was curious about whether the bias would still exist if the research encompassed all organ types.

Donated organs are a lifesaving resource, but there are many more people on the waiting list than there are available organs. We were interested in looking at how we could make small changes to optimize our current supply of deceased donor organs, with the goal of both serving the patients on the waiting list and honoring the gift of life these donors are providing."

Clare E. Jacobson, Study Co-First Author and General Surgery Resident, University of Michigan Health

Using data from the United Network for Organ Sharing, the nonprofit that manages the nation's organ transplant system, Jacobson and her research team found that both OPOs and transplant centers were about 5% less likely to choose organs, regardless of their type, for those aged 70 versus 69. The results suggest that about 1 in 18 donors who are age 70 or older will have no organs selected for transplant, Jacobson said.

"This demonstrated bias is not limited to a single transplant center, OPO or even step in the transplant process and is seen across organ types," Jacobson said. "In our role as stewards of these gifted organs and for all patients waiting for a transplant, interventions must target every step in the transplantation process to overcome our prejudiced thinking."

Of note: Left hand bias was not significant when organ acceptance and selection rates were compared for donors who were 60 versus 59, the researchers found. This may be because, in younger organ donors, age is less heavily weighted compared to metrics like weight, bloodwork and other health problems in the donor, Jacobson said.

Additional authors include Craig S. Brown and Seth A. Waits, both of Michigan Medicine, and Kyle H. Sheetz of the University of California, San Francisco.