The Effect of New Acuity Circle Policy on Simultaneous Liver and Kidney Transplantation in the United States

Abstract

New deceased donor liver allocation policy using an acuity circle (AC)-based model was implemented on February 4th, 2020. The effect of AC policy on simultaneous liver-kidney transplantation (SLKT) remains unknown. The aim of this study was to assess the effect of AC policy on SLKT waitlist mortality, transplant probability, and post-transplant outcomes. Using the United Network for Organ Sharing database, 4908 adult SLKT candidates during two study periods, pre-AC (Aug-2017 to Feb-2020, N=2770) and post-AC (Feb-2020 to Dec-2021, N=2138) were analyzed. Outcomes included 90-day waitlist mortality, transplant probability, and post-transplant patient and graft survival. Compared to pre-AC period, SLKT recipients during post-AC period had higher median model for end-stage liver disease (MELD) score (24 vs 23, P<0.001), and less percentage of MELD exception (4.6% vs 7.7%, P=0.001). The 90-day waitlist mortality was same, but the probability of SLKT increased in post-AC period (P<0.001). Post-AC period also saw increased utilization of donation after cardiac death organs (11% vs 6.4%, P<0.001) and decreased rates of transplantation among Black candidates (7.9% vs 13%). After risk adjustment, post-AC period was not associated with any significant difference in 90-day waitlist mortality (sub-distribution hazard ratio [sHR] 0.80; 95% CI 0.56-1.16, P=0.24), and a higher 90-day probability of SLKT (sHR 1.68; 95% CI 1.41-1.99, P<0.001). During post-transplant period, one-year patient survival, liver and kidney graft survival were comparable between two study periods. The AC liver allocation policy was associated with increased transplant probability of adult SLKT candidates without decreasing waitlist mortality, post-transplant patient survival, or liver and kidney graft survival.