Optimization and simulation models to improve access to organ transplantation in the United States.

Organ allocation in the U.S. is administrated by the United Network of Organ Sharing (UNOS). UNOS’s mission is to ensure fair and equitable allocation of organs as stated in the Code of Federal Regulations, which reads neither place of residence nor place of listing shall be a major determinant of access to transplant . Despite the regulations, there has been endless controversy surrounding the disparity in access to organ transplants. In this context, the primary research goal in this dissertation was to reduce geographic disparity in access to transplants in the U.S., with a focus on heart and kidney transplants. To improve access to heart transplants, we first analyzed the status of geographic disparity and organ utilization under current practice. Next, we used survival analysis and statistical analysis to measure heart utilization rate across the country and studied the factors that can improve heart usage. Additionally, we defined a novel optimization model to modify the geographic boundaries in the U.S. heart allocation system. Finally, We developed a clinically detailed discrete event simulation model for the U.S. heart allocation system to evaluate our proposed changes in in the heart allocation policy stemming from the optimization model. To improve access to kidney transplants, first, we proposed a simulation - optimization approach for better utilization of donated kidneys from living donor through a Kidney Paired Donation (KPD) program. Additionally, to reduce geographic disparity in access to kidney transplants, we used an optimization model to redesign geographic boundaries in the kidney allocation system. Our findings indicated that using optimization and simulation models can greatly improve equity in access to organ transplants