PDF(Pubmed)
Abstract：
The United States (U.S.) Department of Health and Human Services is interested in increasing geographical equity in access to liver transplant. The geographical disparity in the U.S. is fundamentally an outcome of variation in the organ supply to patient demand (s/d) ratios across the country (which cannot be treated as a single unit due to its size). To design a fairer system, we develop a nonlinear integer programming model that allocates the organ supply in order to maximize the minimum s/d ratios across all transplant centers. We design circular donation regions that are able to address the issues raised in legal challenges to earlier organ distribution frameworks. This allows us to reformulate our model as a set-partitioning problem. Our policy can be viewed as a heterogeneous donor circle policy, where the integer program optimizes the radius of the circle around each donation location. Compared to the current policy, which has fixed radius circles around donation locations, the heterogeneous donor circle policy greatly improves both the worst s/d ratio and the range between the maximum and minimum s/d ratios. We found that with the fixed radius policy of 500 nautical miles (NM), the s/d ratio ranges from 0.37 to 0.84 at transplant centers, while with the heterogeneous circle policy capped at a maximum radius of 500 NM, the s/d ratio ranges from 0.55 to 0.60, closely matching the national s/d ratio average of 0.5983. Our model matches the supply and demand in a more equitable fashion than existing policies and has a significant potential to improve the liver transplantation landscape.
摘要：
美国卫生与人类服务部（U.S.）对增加肝脏移植的地理公平性感兴趣。美国的地理差异从根本上说是全国器官供应与患者需求（s/d）比率变化的结果（由于其大小，不能将其视为单个单位）。为了设计一个更公平的系统，我们开发了一个非线性整数规划模型，该模型分配器官供应，以最大化所有移植中心的最小s/d比率。我们设计了循环捐赠区域，能够解决对早期器官分配框架的法律挑战中提出的问题。这使我们能够将模型重新表述为集合分区问题。我们的政策可以被视为异质的捐助圈政策，其中整数程序优化每个捐赠位置周围的圆的半径。与现行政策相比，在捐赠地点周围有固定半径的圆，异质捐助圈政策大大提高了最差s/d比率以及最大和最小s/d比率之间的范围。我们发现，在500海里(NM)的固定半径政策下，移植中心的s/d比率范围从0.37到0.84，虽然异质圈政策的最大半径为500海里，s/d比值范围从0.55到0.60，与全国s/d比值平均值0.5983非常吻合。我们的模型比现有政策更公平地匹配供需，并且具有改善肝移植前景的巨大潜力。
