Kelly Zhou

More than 100,000 people in the United States currently await a kidney transplant, according to the U.S. Department of Health and Human Services. For many of these people on the waitlist, organ donation can be the difference between life and death.

But a recent Yale-led study found significant racial disparities in access to these kidney transplants, concluding that minority patients are less likely to receive a transplant than their white counterparts and tend to wait longer for transplants. The study was published in the Journal of the American Medical Association Surgery on April 3.

The study, led by School of Medicine professor Sanjay Kulkarni, set out to evaluate the success of the recently adopted Kidney Allocation System, introduced in 2014 to mitigate the racial disparities in transplant rates. While the results found that general gaps diminished, inequalities still persisted — particularly during the waiting period for a kidney.

“When people talk about health disparities in transplants, they usually talk about access to the list or who got transplants — but they don’t look at the time period,” said Kulkarni, who also serves a director of the Center for Living Organ Donors.

This novel approach in evaluating the Kidney Allocation System allowed researchers to gain further insight into how the system can be improved. Specifically, the study focused on “active” versus “inactive” designations for people on the waitlist — an indicator of whether the patient is currently ready to receive a transplant or not.

Kulkarni explained that there are several reasons why a patient could be designated inactive, including a medical problem, financial problems, psychosocial issues or out-of-date medical records.

The study found that compared to white patients, black and Hispanic patients who were made temporarily inactive were less likely to regain active status, according to Keren Ladin, assistant professor at Tufts University and secondary author of the study.

As Erich Greene, another author of the study, explained, an inactive status on the waitlist decreases a patient’s options for transplants because they can only receive kidneys from living donors. On the other hand, active waitlist members can receive a kidney from a deceased donor, which is where most donations come from.

According to Kulkarni, most Americans wait around five to seven years to receive their kidney transplants.

The researchers also focused on “highly sensitized” patients — those who are more likely to reject a kidney transplant due to sensitivity to antibody proteins on the kidney, according to Yanhong Deng, another author of the study.

“Compared to white patients, black patients who are highly sensitized have a lower probability of transplant,” said Ladin.

Moving forward, Kulkarni said he recommends that transplant and dialysis centers work together to increase access to transplants. He explained that since many of these practices are private for-profit organizations, they currently have little incentive to collaborate.

One possibility to address this issue, Kulkarni proposed, was incorporating how easily a clinic can change “inactive” patient status to “active” into Medicare’s current quality metrics for healthcare practices.

Deng added that their statistical methods were unique in representing the possibilities of patients switching between active and inactive status, adding complexity to their model.

The study was funded by Alexion, a pharmaceutical company headquartered in New Haven that sponsored Kulkarni. The company was interested in the statistical methodology, which may be helpful for deciding which drugs to develop in the future, according to Greene.

Jessica Pevner |