Structural Estimation of Kidney Transplant Candidates' Quality of Life Scores : Improving National Kidney Allocation Policy Under Endogenous Patient Choice and Geographical Sharing

We develop a data-driven framework for assessing the impact of changes to the deceased-donor kidney allocation policy taking into account the transplant candidates' (endogenous) organ acceptance behavior and sharing among different locations under UNOS' geographically tiered allocation structure. To be specific, we develop a dynamic structural model of the transplant candidates' accept/reject decisions for organ offers. Our model of the national list (and its geographic structure) can be incorporated into the Kidney Pancreas Simulation Allocation Model (KPSAM) that is used to inform policy makers. Moreover, it allows important features of the transplant system such as the degree of tissue matching, changes in the health status of the transplant candidates as they wait on the list, organ quality, geographical sharing and cold-ischemia time of the organs as well as the heterogeneity in transplant candidates' quality of life scores. Using United Network of Organ Sharing (UNOS) data on transplant candidates, donors, organ offers, and follow up results on transplant outcomes, we estimate the transplant candidates' quality of life scores on dialysis versus post transplant. Our estimates yield similar results on average to what is typically assumed in the medical literature. However, they differ significantly when patient and donor characteristics are considered. We then consider policy proposals that have been considered by UNOS. This counterfactual analysis helps assess the (unintended) consequences of such policies. We find that although the current policy increases the total number of transplants by 2.63% and total life years by 4.45%, it decreases total quality adjusted life years by 1.68%. Moreover, it increases the disparity in probability of getting a transplant for patients of different health scores by 69.3% whereas it decreases disparity across patients with different sensitization (CPRA) scores. These happen due to the current prioritization of healthier patients for kidneys of better quality. Our results reveal that geographical redistricting of the transplant system, as done for the liver allocation system, does not change the system performance significantly. Hence, it should not be implemented. However, the brevity matching policy, currently being considered by UNOS, can further increase the total number of transplants by 1.50%, and is worth considering further