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

Background: 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.Methods: 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. Results: 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. Conclusions: 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.