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

Abstract

The number of kidney after liver transplants (KALT) increased after the implementation of the United Network of Organ Sharing (UNOS) safety net policy, but the effects of the policy on KALT outcomes remain unknown. Using the UNOS database, we identified KALT between 60 and 365 days from liver transplant from January 1, 2010, to December 31, 2020. The main outcome was 1- and 3-year patient, liver, and kidney graft survival. Secondary outcomes included 6-month and 1-year acute rejection (AR) of liver and kidney, and 1-year kidney allograft function. 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 liver transplant. 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-policy versus pre-policy (1.4 vs. 1.3 mg/dL, p=0.07) despite a higher proportion of deceased donors, higher Kidney Donor Profile Index, and longer kidney cold ischemia time post-policy (p<0.05 for all). This 3-year follow-up after the 2017 UNOS policy revision demonstrated that the safety net implementation has resulted in improved liver outcomes for patients who underwent KALT with no increased AR of the liver or the kidney allografts.

Priority for kidney after liver transplantation: A safety net for all?

“…Attieh and colleagues have provided an important update on the safety net policy, utilizing the United Network for Organ Sharing database to evaluate outcomes associated with KALT before and after implementation of the safety net policy in 2017, identifying 256 patients who received KALT between 60 and 365 days after LT from the years 2010 to 2020. Their analysis included 1- and 3-year patient, liver, and kidney graft survival in addition to the incidence of acute rejection and post-KALT kidney graft function 9 . Similar to earlier reports, this update noted that the use of KALT increased following the implementation of the safety net policy while maintaining acceptable kidney graft, liver graft, and patient survival.…”

Kidney after liver transplantation does not have an increased risk of rejection compared to liver alone

“…The role of dual organ versus single organ transplants in the risk of rejection has been extensively debated in the literature. 5,[16][17][18][19][20] The general implication of this data suggests that there is a protective effect on the risk of rejection in the context of dual organ transplant. However, the introduction of "safety net" kidney after liver transplantation raises the question of how the delay in second organ transplantation might impact rejection rates.…”

Kidney after Liver Transplantation for All

“…There is also evidence of post-policy increase in kidney-after-liver transplantation. 1 the higher risk in this subset of simultaneous liver-kidney transplant recipients attributable kidney failure or due to systemic causes leading to higher risk of death, irrespective of number of organs transplanted? Actionable characteristic of recipients who survived the first 90 days after transplant might be important information to ascertain because this may help develop better medical eligibility criteria because futility of transplant would have largely been answered in this group.…”

“…Initial analysis of the effect of this policy on simultaneous liver-kidney and liver transplant outcomes was very encouraging, with evidence of decrease in percent simultaneous liver-kidney transplantation from 9.7% pre-policy to 8% in 2022 (Figure 1), increase in liver transplantalone listing for liver transplant candidates on dialysis, decrease in simultaneous liver-kidney transplant listing, increase in kidney-after-liver listing and transplantation while maintaining comparable waitlist and liver transplant outcomes, comparable patient and kidney survivals between simultaneous liverkidney and kidney-after-liver recipients, comparable kidney outcomes in kidney-after-liver versus kidneyalone transplants, and a signal toward improvement in liver graft survival in kidney-after-liver transplant recipients, post-policy. 1,[7][8][9] Despite these welcoming results, the transplant community is still skeptical regarding the kidney-after-liver transplantation under the safety net policy.…”

“…The percentage of simultaneous liver-kidney transplantation (number of simultaneous liver-kidney/number of liver transplant), however, has declined from 9.7% pre-policy to 8% in 2022 (source: www.unos.org). There is also evidence of post-policy increase in kidney-after-liver transplantation 1. COVID-19, coronavirus disease 2019; MELD, Model for End-Stage Liver Disease; OPTN, Organ Procurement and Transplantation Network; SLK, simultaneous liver-kidney.…”