Simulation modeling of the impact of proposed new simultaneous liver and kidney transplantation policies.

Background: Increasing use of kidney grafts for simultaneous liver and kidney (SLK) transplants is causing concern about the most effective utilization of scarce kidney graft resources. This study evaluated the impact of implementing the proposed United Network for Organ Sharing SLK transplant policy on outcomes for end-stage liver disease (ESLD) and end-stage renal disease (ESRD) patients awaiting transplant.

Methods: A Markov model was constructed to simulate a hypothetical cohort of ESLD patients over a 30-year time horizon starting from age 50. The model applies the different criteria being considered in the United Network for Organ Sharing policy and tallies outcomes, including numbers of procedures and life years after liver transplant alone (LTA) or SLK transplant.

Results: When 1-week pretransplant dialysis duration is required, the numbers of SLK transplants and LTAs would be 648 and 9,065, respectively. If the pretransplant dialysis duration is extended to 12 weeks, there would be 240 SLK transplants and 9,426 LTAs. This change results in a decrease of 6,483 life years among SLK transplant recipients and an increase of 4,971 life years among LTA recipients. However, by increasing the dialysis duration to 12 weeks from 1 week, 408 kidney grafts would be released to the kidney waitlist because of the decline in SLK transplants; this yields 796 additional life years gained among ESRD patients.

Conclusion: Implementation of the proposed SLK transplant policy could restore access to kidney transplants for patients with ESRD albeit at the detriment of patients with ESLD and renal impairment.