Removing geographic boundaries from liver allocation: A method for designing continuous distribution scores.

Area of Science:

• Organ transplantation research
• Computational biology
• Health policy analysis

Background:

• The Organ Procurement and Transplantation Network (OPTN) is shifting from geographic liver allocation to a continuous distribution model.
• This new model utilizes a composite allocation score (CAS) based on medical urgency, candidate biology, and placement efficiency.
• Implementing new prioritization variables requires extensive consensus-building, but existing priorities can be rapidly translated into CAS.

Purpose of the Study:

• To design a minimally disruptive composite allocation score (CAS) for liver allocation.
• To eliminate geographic boundaries in organ distribution.
• To reduce waitlist deaths without negatively impacting vulnerable patient groups.

Main Methods:

• Utilized simulation with optimization to develop the CAS.
• Ensured the CAS minimally impacted existing prioritization schemes.
• Validated the CAS against the Acuity Circles (AC) system over a 3-year simulation period.

Main Results:

• The optimized CAS decreased liver transplant waitlist deaths from 7771.2 to 7678.8 compared to Acuity Circles.
• Average and median travel distances for liver allocation were reduced.
• Travel distances increased for high MELD and status 1 candidates but decreased overall, indicating a more efficient distribution.

Conclusions:

• The developed CAS effectively reduces waitlist deaths by optimizing organ placement for high-urgency candidates.
• This computational approach allows for flexible score weighting to achieve specific allocation outcomes.
• The method provides a framework for future adjustments to liver allocation priorities.