Access to kidney transplantation among pediatric candidates with prior solid organ transplants in the United States

Background Pediatric kidney transplant candidates require timely access to transplant to optimize growth and neurodevelopmental outcomes. We studied access to transplant for pediatric candidates with prior organ transplants. Methods We used US registry data to identify pediatric kidney transplant candidates added to the waiting list 2015-2019 and used competing risk regression to study the association between prior transplant status and probability of receiving a kidney transplant, treating wait-list removal and death as competing events. Results Of 4962 pediatric kidney transplant candidates included, 89% had no prior transplant and 11% had received a prior organ transplant (kidney 87%, liver 5%, heart 5%). Prior transplant recipients were older at listing (median 15 vs. 12 years) and more likely to have PRA >= 98% (22% vs. 0.3%) (both p < .001). There was no significant difference in the proportion of candidates from each group who were preemptively wait-listed. Unadjusted competing risk regression showed a lower risk of kidney transplant after wait-listing among candidates with prior organ transplant (HR 0.52, 95%CI 0.47-0.59, p < .001). This association remained significant after adjusting for candidate characteristics (HR 0.73, 95%CI 0.63-0.83, p < .001). Among deceased donor kidney recipients, median KDPI was similar between groups, but recipients with prior transplants were more likely to receive kidneys from donors with hypertension (4% vs. 1%, p = .01) and donors after cardiac death (11% vs. 4%, p < .001). Conclusions Pediatric kidney transplant candidates with prior organ transplants have reduced access to transplant after wait-listing. Allocation system changes are needed to improve timely access to transplant for this vulnerable group.