New algorithms to score candidates for lifesaving organ donations

COVID-19 has been in the spotlight not only in the news, but also in how technologies are being developed to evaluate and control the spread of the virus. For example, various state guidelines outline how ventilators, personal protective equipment, and COVID-19 vaccines should be prioritized in hospitals, ambulances, and communities, respectively. But while the pandemic illuminated how government algorithms shape the way healthcare resources are allocated throughout the country, government algorithms will continue to inform urgent healthcare decisions beyond the pandemic. And one of the services impacted in this is the allocation of organs for transplant.

A new score-based framework is updating the Organ Procurement and Transplant Network (OPTN), the national system for distributing lung, liver, kidney and other lifesaving organ donations. Individual organ systems have been transitioning to this new framework since the OPTN Board of Directors approved it in 2018: lung allocation was the first to be updated in January 2019, and liver, kidney, and pancreas allocations were updated last month. Rather than reviewing transplant candidates in ranked classifications and within fixed areas, these new algorithms continually calculate composite scores for candidates that weigh factors related to medical urgency, placement efficiency, outcomes, and patient access. A higher score puts a patient higher on the waitlist, and in turn, more likely to receive an organ transplant. This framework is supposed to be more equitable and adaptable to future changes, but as seen in the recent pushback against new kidney policies in particular, critics have argued that this change will increase wait times and give differential treatment to patients in densely populated regions. 

Organ transplantation is the leading form of treatment for patients with severe organ failure. There were over 32,000 organ transplants in 2019, and an average of 95 transplants now take place in the U.S. everyday. Unlike other life saving transplants (like those involving blood or bone marrow), most organ donations come from deceased donors. Unfortunately, there are not enough donations to meet organ transplant needs across the country: In 2020, about 110,000 people remained on national waiting lists, and currently, there are over 120,000 people in need of a life saving transplant. Someone is added to the national transplant waiting list every nine minutes, and over 20 people die waiting for an organ donation each day. 

Organ allocation systems not only determine who receives scarce organ donations but also what that medical care looks like. In addition to affecting wait times, allocation systems take into account compatibility between donors and patients, which affects the likelihood of transplant success. Transplant candidates are screened if medical factors like blood type or weight make them incompatible with an organ donor. The new allocation algorithms will also be flexible enough to account for factors unique to each organ type. For example, immune system compatibility is important when matching kidney donors to recipients

Changes made to OPTN’s decision-making framework will affect all organ donations in the country: every transplant hospital, organ procurement organization and histocompatibility lab in the U.S. is connected through a nonprofit organization that supports OPTN in partnership with the federal government. Not only does the national organ allocation system have life-or-death implications for many patients across the country, but it also has an important role in shaping systemic issues of access and equity in American healthcare. Recent research has shown how prior models have led to a disparity in the care that African-American chronic kidney disease patients receive, including transplantation access, for example. Women also had less access to kidney transplantation compared to white men under the prior model. Like other attempts to maximize efficiency of limited resources using data-driven analytics, academics warn against the ethical issues  that may arise with algorithm-based organ allocation decisions. For example, programs listing liver transplant candidates were able to game a previous algorithm used to prioritize liver donations, and a previous proposal for a kidney allocation algorithm based primarily on longevity would have violated the Age Discrimination Act. Considering ethics upfront — designing allocation models around metrics of not only efficiency but also ethics — is particularly important given the high-stakes implications of organ allocation.

Journalists can follow along with organ-specific updates from OPTN, the Department of Health and Human Services, and other organizations to cover these algorithms as they continue to be adopted through 2023. Journalists can also research the legal and regulatory history of organ distribution in the U.S., community input considered in the development of the continuous distribution model, and tools related to organ allocation. For example, OPTN made an interactive dashboard to simulate comparisons and match runs. Furthermore, while organ allocation is organized and overseen at a national level, journalists could consider how this new framework impacts states, local communities, hospitals, and individuals, such as by investigating doctors’ and patients’ criticisms of the new systems. Journalists could also consider how these changes to OPTN occur in the context of recent policies concerning organ procurement organizations included in the national network. 

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