Safety Net’s Kidney After Liver Transplant Linked to Reduced eGFR

Findings from a recent study are providing clinicians with an overview of kidney allograft outcomes for kidney after liver transplantation (KALT) versus simultaneous liver-kidney transplantation (SLKT) in the "safety net" era.1

Leveraging Organ Procurement and Transplantation Network (OPTN)/United Network for Organ Sharing (UNOS) data, the study highlights similar allograft survival between transplantation modalities but reduced estimated glomerular filtration rate (eGFR) in KALT recipients.1

In August 2017, the Organ Procurement and Transplantation Network (OPTN) established specific criteria for SLKT: chronic renal insufficiency, sustained acute kidney injury, or the presence of a metabolic disease associated with the development of renal failure. Recognizing that the new policy could cause patients who benefit from a renal transplant to not receive one, they established a “safety net” protocol to allocate kidney allografts to liver transplant recipients with persistent renal dysfunction within 1 year after liver transplantation.1,2

“This study is the first to assess OPTN/UNOS kidney allograft outcomes in those who underwent SLKT compared to KALT during the actual safety net era,” wrote study investigator Brian Lee, MD, a transplant hepatologist working at the Hoag Digestive Health Institute.1

Lee and colleagues conducted a retrospective cohort study using data from the OPTN/UNOS database of patients who underwent primary kidney transplantation via the SLKT or safety net KALT pathway between January 2018 and December 2021. They compared kidney allograft survival, patient survival, eGFR, and kidney rejection between the groups. Propensity score analysis was utilized to assess the differences in eGFR and rejection.1 

The study included adults ≥ 18 years of age who underwent SLKT (n = 2620) and KALT (n = 526). At baseline, ​​compared to patients who underwent SLKT, those who received KALT were more frequently male (67.1% vs 58.2%, P <.001) and Caucasian (73.8% vs 62.9%, P <.001), but investigators noted age was similar between the 2 groups.1

From the findings, investigators reported a 36.3% prevalence of diabetes mellitus in KALT compared to 43.2% in SLKT (P = .003). There was a 43.0% instance of alcohol as the reason for liver transplantation in KALT compared to 30.8% in SLKT (P <.001), and a 73.2% frequency of dialysis before transplant compared to 53.5% (P <.001).1

At 1-year post-kidney transplant, investigators noted similar kidney allograft survival rates, with 97.7% for KALT (95% Confidence Interval [CI], 96.0 to 98.7) and 96.8% for SLKT (95% CI, 96.0 to 97.4; P = .43). Patient survival rates were increased in KALT with a rate of 96.7% (95% CI, 94.8 to 98.0) compared to 93.9% in SLKT (95% CI, 92.9 to 94.8; P = .02).1

Investigators reported consistently reduced eGFR in patients with KALT at 6 months, 1 year, and 3 years after kidney transplantation. At 1 year, the mean difference between KALT and SLKT was −6.6 mL/min/1.73 m2 (95% CI, −8.5 to −4.7; P <.001) in the unadjusted and −4.7 mL/min/1.73 m2 (95% CI, −7.0 to −2.4; P <.001) in the propensity score matched analysis. At 3 years, the mean difference was −6.3 mL/min/1.73 m2 (95% CI, −8.8 to −3.7; P <.001) in the unadjusted and −3.8 mL/min/1.73 m2 (95% CI, −6.5 to −1.1; P = .005) in the propensity score matched analysis.1

Lee and colleagues also reported increased rates of rejection in KALT in 6 months, 1 year, and 3 years compared to SLKT, but upon propensity score-matched analysis, did not observe significant differences in rejection at any of these time points.1

“Future studies should include longer-term follow-up to determine if kidney allograft health in safety net recipients remains optimal or if allograft failure results in re-transplantation and/or mortality,” investigators concluded. “Additionally, center-based studies assessing granular data on the type of immunosuppression used, rejection characteristics, and other variables are warranted.”1

References

1. Lee BT, Dodge JL, Voora S, Ahearn A, Fong T. Comparison of Kidney Allograft Outcomes in Simultaneous Liver‐Kidney Versus Kidney After Liver Transplantation Since the Safety Net Era. Clinical Transplantation. 2025;39(12). doi:https://doi.org/10.1111/ctr.70407

2. Altshuler PJ, Shah AP, Frank AM, et al. Simultaneous liver kidney allocation policy and the Safety Net: an early examination of utilization and outcomes in the United States. Transplant International. 2021;34(6):1052-1064. doi:https://doi.org/10.1111/tri.13891