Changes in Deceased Donor Kidney Transplantation One Year After KAS Implementation

Abstract

After over a decade of discussion, analysis, and consensus-building, a new kidney allocation system (KAS) was implemented on December 4, 2014. Key goals included improving longevity matching between donor kidneys and recipients and broadening access for historically disadvantaged subpopulations, in particular highly sensitized patients and those with an extended duration on dialysis but delayed referral for transplantation. To evaluate the early impact of KAS, we compared Organ Procurement and Transplantation Network data 1 year before versus after implementation. The distribution of transplants across many recipient characteristics has changed markedly and suggests that in many ways the new policy is achieving its goals. Transplants in which the donor and recipient age differed by more than 30 years declined by 23%. Initial, sharp increases in transplants were observed for Calculated Panel-Reactive Antibody 99-100% recipients and recipients with at least 10 years on dialysis, with a subsequent tapering of transplants to these groups suggesting bolus effects. Although KAS has arguably increased fairness in allocation, the potential costs of broadening access must be considered. Kidneys are more often being shipped over long distances, leading to increased cold ischemic times. Delayed graft function rates have increased, but 6-month graft survival rates have not changed significantly.

Early Experience with the New Kidney Allocation System

“…The most visible success of KAS has, in fact, been to increase transplant opportunities for highly sensitized patients. Although the most highly sensitized (calculated panel reactive antibodies [CPRAs] of 99%-100%) candidates represented about 8% of the waiting list, they received only 2% of deceased donor kidney transplants before KAS but now account for 10% of transplants (1,2). Before KAS, many of these recipients had little or no realistic expectation for receiving a deceased donor kidney transplant.…”

“…Although short-term graft and patient survival rates have changed little, the percentage of recipients experiencing delayed graft function has risen from just under 25% to over 30%, driven largely by the increase in transplants to patients with high dialysis duration (1). The delayed graft function rate has declined somewhat as this bolus effect has tapered (2).…”

“…System performance has been monitored closely (1). Although the kidney allocation system (KAS) has clearly achieved some of its goals, progress toward others remains either elusive or unclear.…”

Adult Liver Allocation in Eurotransplant

“…Riskadjusted models could allow more refined prediction and monitoring of suggested and implemented allocation changes 35,36 and have already been implemented in the USA and UK where they actively contribute to the evaluation and continuous improvement of the allocation systems. 34 Implementation of such advanced evidence based allocation policy development needs continued and close collaborative efforts between the national Competent Authorities, the national transplant societies, the transplant centers, and Eurotransplant to optimize not only return of detailed follow-up data to the Registry but also analyses of these data and construction of predictive models for suggested allocation changes.…”

Perspectives on the Strengths and Weaknesses of the National Kidney Allocation System

“…Changing an entrenched system is hard, and KAS was born of the hard work and dedication of six Organ Procurement and Transplantation Network Kidney Committee Chairpersons, 167 different committee members, two national consensus conferences, and two formal requests for public comment (3). In all, the process took 12 years.…”