The encyclopedia · R&D & Science · Operational decision · 2002
US liver allocation switched from discretion to an objective score, and got fairer
In 2002 the US began allocating donor livers by a validated MELD score, which reduced waiting-list deaths and removed a racial bias.
United Network for Organ Sharing (UNOS)
the move
Donor livers are scarce, and the pre-2002 US allocation ranked patients by broad urgency status categories and time on the list, so patients within a category were not separated by how close they were to dying.
In February 2002 the system was anchored to the Model for End-Stage Liver Disease (MELD) and its pediatric version PELD, an objective score that predicts a patient's risk of death within three months.
A JAMA study of the UNOS waiting list found that before MELD, black patients were more likely than white patients to die or become too sick for transplant (27.0% vs 21.7%) and were less likely to receive a transplant; after MELD those disparities were no longer statistically significant.
Because the score ranks by urgency and also predicts post-transplant need, it aligned the system with evidence rather than with a local committee's call.
why it works
- An objective score replaces judgment calls that can be second-guessed or biased.
- Ranking by predicted mortality reduces deaths on the waiting list.
- A validated, transparent measure is more defensible than a discretionary committee.
- It aligns urgency with expected benefit, so the sickest and the most likely to do well are both served.
what transfers
When you must ration something life-or-death, make the tie-breaker an objective, validated measure.
what came after
MELD/PELD, refined by exception scores and later by a 2018 continuous-distribution rule, remained the basis of US liver allocation and became the model for evidence-based organ allocation worldwide.
references
- Disparities in liver transplantation before and after introduction of the MELD score
- Questions and Answers About Liver Allocation
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