Removing administrative boundaries using a gravity model for a national liver allocation system.

Area of Science:

• Organ transplantation research
• Medical policy reform
• Public health disparities

Background:

• Geographic disparities in organ allocation policies create inequities.
• Discrete geographical models and artificial boundaries hinder access for critically ill patients.
• Current organ allocation systems may not adequately address patient urgency versus organ proximity.

Purpose of the Study:

• To introduce and evaluate a continuous geographical allocation model using a gravity model.
• To assess the impact of this new model on organ access, waitlist outcomes, and survival.
• To provide an equitable and efficient alternative to traditional geographical organ allocation methods.

Main Methods:

• Development of a continuous geographical allocation model incorporating a gravity model.
• Introduction of a multiplicative interaction between patient condition (MELD score) and distance to the graft.
• Comparative analysis with the previous French liver allocation scheme.

Main Results:

• Reduced transplantations for candidates with Model for End-Stage Liver Disease (MELD) ≤14 from 10.3% to 0.6%.
• Decreased 1-year waitlist death and delisting rates for MELD ≥35 from 30.1% to 22.4%.
• Improved waiting list survival (CHR 0.84) and post-transplant survival (HR 0.83).

Conclusions:

• The continuous gravity model ensures more equitable access to liver transplants.
• This model offers an efficient and safe alternative to administrative boundaries in geographical organ allocation.
• Implementation of the gravity model enhances overall outcomes for liver transplant recipients.