title: Improving Liver Allocation Using Optimized Neighborhoods.
abstract: Geographic disparities persist in access to liver transplantation. Candidates with similar urgency experience varying opportunities for transplants across the United States. Policymakers are poised to act and 1 proposal entails reorganizing the current Organ Procurement and Transplant Network (OPTN) of 11 regions into 8 districts. However, redistricting has the shortcomings that Organ Procurement Organizations (OPOs) are disconnected from their immediate neighbors by district borders and that it is not easily responsive to uncertainty resulting from variability in donor and listing rates.
  
  
  
  We introduce the notion of an OPO's neighborhood-a collection of donor service areas (DSA) surrounding the OPO that acts as the OPO's region in the current local-regional-national framework. Districts and concentric circles are special cases. We design 58 neighborhoods for the DSAs with several attractive properties and optimize them to balance supplies and demands using 10 years of Organ Procurement and Transplant Network data. We conduct a simulation experiment comparing current allocation, redistricting, and neighborhoods under current sharing policies with respect to the following metrics: total mortalities, DSA-average model for end-stage liver disease (MELD) at transplant, DSA-average MELD standard deviation, and average organ transport distance. Liver-simulated allocation model cannot accommodate neighborhoods, so we programmed a discrete-event simulator, LivSim, to approximate liver-simulated allocation model.
  
  
  
  We exhibited a neighborhood solution. Compared with the current allocation, simulation results showed that neighborhoods reduce the DSA-average MELD standard deviation by 29% and save about 65 lives annually. Compared with redistricting, the neighborhoods had smaller average transport distances that were more uniform across DSAs, saved about 20 additional lives, and reduced DSA-average MELD standard deviation by an additional 17%.
  
  
  
  Alternatives to redistricting with desirable properties and performance are possible and should be considered.
authors.affiliation: 1 Industrial Engineering and the Management Sciences, Northwestern University, Evanston, IL. 2 Center for Engineering and Health, Institute for Public Health and Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL. 3 Comprehensive Transplant Center, Northwestern University Transplant Outcomes Research Collaborative (NUTORC), Northwestern University Feinberg School of Medicine, Chicago, IL.
authors.forename: Vikram
authors.initials: V
authors.lastname: Kilambi
authors.forename: Sanjay
authors.initials: S
authors.lastname: Mehrotra
mesh_terms: D002391:Catchment Area, Health; D003198:Computer Simulation; D015276:Health Care Rationing / Q000458:organization & administration*; D006301:Health Services Needs and Demand / Q000458:organization & administration*; D054625:Healthcare Disparities; D006801:Humans; D016031:Liver Transplantation / Q000379:methods*; D020380:Needs Assessment; D011050:Policy Making; D012040:Regional Health Planning / Q000458:organization & administration; D012111:Residence Characteristics; D013997:Time Factors; D061665:Time-to-Treatment; D014019:Tissue Donors / Q000600:supply & distribution*; D009927:Tissue and Organ Procurement / Q000458:organization & administration*; D014187:Transportation of Patients / Q000458:organization & administration; D014481:United States; D014850:Waiting Lists