Improved outcomes of kidney-after-liver transplantation after the implementation of the safety net policy

Background: The number of kidney after liver transplants (KALT) increased after the implementation of the UNOS safety net policy but the effects of the policy on KALT outcomes remain unknown. Methods: Using the UNOS database, we identified KALT between 60 and 365 days from liver transplant (LT) from 1/1/2010 to 12/31/2020. The main outcome was 1- and 3-year patient, liver and kidney graft survival. Secondary outcomes inlcuded 6-month and 1-year acute rejection (AR) of liver and kidney, and 1-year kidney allograft function. Results: Of the 256 KALT, 90 were pre-policy and 166 post-policy. Compared to pre-policy, post-policy 1- and 3-year liver graft survival was higher (54% and 54% vs. 86% and 81% respectively, p<0.001) while 1- and 3-year kidney graft survival (99% and 75% vs. 92% and 79% respectively, p=0.19), and 1- and 3-year patient survival (99% and 99% vs. 95% and 89% respectively, p=0.11) were not significantly different. Subgroup analysis revealed similar trends in patients with and without renal failure at LT. Liver AR at 6 months was lower post-policy (6.3% vs. 18.3%, p=0.006) but was similar (10.5% vs. 13%, p=0.63) at 1-year. Kidney AR was unchanged post-policy at 6 months and 1-year. Creatinine at 1-year did not differ post- versus pre-policy (1.4 mg/dL vs. 1.3 mg/dL, p=0.07) despite higher proportion of deceased donor, higher kidney donor profile index (KDPI), and longer kidney cold ischemia time post-policy (p<0.05 for all). Conclusions: This 3-year follow-up after the 2017 UNOS policy revision demonstrated that the safety net implementation has resulted in improved liver outcomes for KALT patients with no increased AR of the liver or the kidney allografts.