Lack of Benefit and Potential Harm of Induction Therapy in Simultaneous Liver-Kidney Transplants

The number of simultaneous liver-kidney transplantations (SLKTs) and use of induction therapy for SLKT have increased recently, without much published evidence, especially in the context of maintenance immunosuppression containing tacrolimus (TAC) and mycophenolic acid (MPA). We queried the Organ Procurement and Transplant Network registry for SLKT recipients maintained on TAC/MPA at discharge in the United States for 2002-2016. The cohort was divided into 3 groups on the basis of induction type: rabbit antithymocyte globulin (r-ATG; n = 831), interleukin 2 receptor antagonist (IL2RA; n = 1558), and no induction (n = 2333). Primary outcomes were posttransplant all-cause mortality and acute rejection rates in kidney and liver allografts at 12 months. Survival rates were analyzed by the Kaplan-Meier method. A propensity score analysis was used to control potential selection bias. Multivariate inverse probability weighted Cox proportional hazard and logistic regression models were used to estimate the hazard ratios (HRs) and odds ratios. Among SLKT recipients, survival estimates at 3 years were lower for recipients receiving r-ATG (P = 0.05). Compared with no induction, the multivariate analyses showed an increased mortality risk with r-ATG (HR, 1.29; 95% confidence interval [CI], 1.10-1.52; P = 0.002) and no difference in acute liver or kidney rejection rates at 12 months across all induction categories. No difference in outcomes was noted with IL2RA induction over the no induction category. In conclusion, there appears to be no survival benefit nor reduction in rejection rates for SLKT recipients who receive induction therapy, and r-ATG appears to increase mortality risk compared with no induction.