The New Distance-Based Kidney Allocation System: Implications for Patients, Transplant Centers, and Organ Procurement Organizations

Abstract

Purpose of Review The goal of deceased donor kidney allocation policy is to provide objective prioritization for donated kidneys, and policy has undergone a series of revisions in the past decade in attempt to achieve equity and utility in access to kidney transplantation. Most recently, to address geographic disparities in access to kidney transplantation, the Kidney Allocation System changed to a distance-based allocation system—colloquially termed “KAS 250”—moving away from donor service areas as the geographic basis of allocation. We review the early impact of this policy change on access to transplant for patients, and on complexity of organ allocation and transplantation for transplant centers and organ procurement organizations. Recent Findings Broader sharing of kidneys has increased complexity of the allocation system, as transplant centers and OPOs now interact in larger networks. The increased competition resulting from this system, and the increased operational burden on centers and OPOs resulting from greater numbers of organ offers, may adversely affect organ utilization. Preliminary results suggest an increase in transplant rate overall but a trend toward higher kidney discard and increased cold ischemia time. Summary The KAS 250 allocation policy changed the geographic basis of deceased donor kidney distribution in a manner that is intended to reduce geographic disparities in access to kidney transplantation. Close monitoring of this policy’s impact on patients, transplant center behavior, and process measures is critical to the aim of maximizing access to transplant while achieving transplant equity.

Beyond donation to organ utilization in the USA

“…Notoriously underutilized [17,18] pancreata and intestines have only seen further increases in NUR DON , which have risen to 83.8 and 99.4%, respectively, over the past decade. The recent rise in kidney NUR REC to over 26% has received significant attention [19][20][21] and is likely attributable to multiple factors, including recent broadening of the donor pool by pursuing donors with one or multiple features previously considered unfavourable; the COVID-19 pandemic [22,23]; 250 nm circle-allocation starting in March 2021 [24 ,25]; and inability of transplant hospitals' capacity to adapt quickly enough to the ongoing rise in organ availability.…”

“…Placement inefficiency takes two primary forms: the increased costs, logistical complexity and resource utilization associated with transporting organs over greater distances; and the underutilization of organs mediated by increased offer refusals and ensuing increases in cold ischemia time (CIT). In substantially altering the role of the recipient's proximity to the donor in all allocation policies, the emphasis of recent policy projects has been on fostering geographic equity, and evidence suggests these changes have sacrificed placement efficiency [20,21,24 ▪ ,41,42].…”

Geography, inequities, and the social determinants of health in transplantation

“…OPOs do not correlate with any of the above levels, so must be assessed at the donor or center level. As allocation in the United States has changed to circles around the donor hospital, the metrics of access to donors have reverted to nautical miles ( 31 , 32 ).…”

Wasted Potential: Decoding the Trifecta of Donor Kidney Shortage, Underutilization, and Rising Discard Rates

“…Continuous reforms in allocation policies have aimed to tackle the high discard rate and inequity within the allocation system. In 2021, the newest iteration of the Kidney Allocation System (KAS), termed KAS 250, was implemented with the aim of reducing geographic disparities in kidney transplantation [5]. KAS 250 replaced the donation service area (DSA) and Organ Procurement and Transplantation Network (OPTN) region distribution system with a distance-based system, offering kidneys first to candidates listed at transplant hospitals within 250 nautical miles of the donor hospital [6].…”