Current Kidney Transplant Policies Disadvantage Certain Adolescents, Young Adults

Justin Steggerda, MD

Credit: Cedars-Sinai

New research is shedding light on inequities posed by the “pediatric advantage” of current kidney transplant allocation policies, which disadvantage patients who initiated dialysis as children but were not waitlisted until after 18 years of age.¹

Leveraging waitlist registration and transplant outcome data from the OPTN Standard Transplant and Research (STAR) file, the study found patients who initiated dialysis at a younger age but were not listed until ≥ 18 years of age do not reap the pediatric advantages of obtaining a high-quality deceased donor organ. Rather, these patients are the most likely to be removed from the waitlist, spend the longest time on dialysis, have the longest allocation time, and demonstrate the worst graft survival.¹

“Current allocation policies benefit patients who are listed before turning 18, without recourse for individuals who are on dialysis as pediatric patients but are not listed until after becoming an adult,” Justin Steggerda, MD, an abdominal transplant and hepatobiliary surgeon at Cedars-Sinai, and colleagues wrote.¹

Following the initiation of the Kidney Allocation System in 2014, pediatric candidates waitlisted before 18 years of age gained advantages for allocation time and sequencing versus adult candidates. In order to obtain this “pediatric advantage,” patients must complete kidney transplant evaluation and be waitlisted before turning 18 years old, but not all pediatric dialysis patients are referred or approved for transplantation early enough to gain this heightened priority.^1,2

To evaluate the outcomes of patients who initiated dialysis before, but were not waitlisted until after, turning 18 years old, investigators examined data for patients 11-25 years of age who were waitlisted for kidney transplantation between 2001 and 2022. Those who were listed for or received a multiorgan transplant and who underwent a living donor kidney transplant (LDKT) were excluded from the analysis.¹

Overall, 35,764 waitlist registrations were identified, of which 10,252 underwent LDKT, leaving 25,512 candidates for evaluation. Of those patients, 9408 (36.9%) were pediatric candidates waitlisted before 18 years of age and 16,104 (63.1%) were young adult candidates waitlisted after 18 years of age.¹

Patients were also classified based on their dialysis status at the time of listing, including not yet on dialysis (NYOD) and on dialysis (OD). Additionally, YA groups were further categorized based on their age at dialysis initiation, including those who started dialysis before 18 years of age but were not waitlisted until after 18 years of age (YA + OD < 18) and those who started dialysis after age 18 and were subsequently waitlisted (YA + OD ≥ 18).¹

The primary outcomes of interest were progression to transplant and graft survival after transplant across the 5 cohorts of patients.¹

During the study period, 84.9% of pediatric OD candidates and 64.7% of pediatric NYOD candidates received a DDKT, compared with 59.0% of YA + OD < 18 and 57.3% of YA + OD ≥ 18 candidates (P <.001).¹

Investigators noted pediatric + OD candidates had the highest likelihood of transplant at all time points, which was sixfold greater than YA + OD < 18 patients at 5 years after listing. In contrast, YA + OD < 18 candidates had the highest rate of death and worsening condition leading to waitlist removal.¹

Pediatric + OD recipients had the shortest median time from waitlist to transplant at 178 (Interquartile range [IQR], 59–433) days, while it was longest for YA-NYOD candidates (1008; IQR, 419–1706 days; P <.001). Time from dialysis initiation to transplant was shortest for Peds-NYOD recipients and longest for YA + OD < 18 recipients (P <.001).¹

Investigators pointed out YA + OD < 18 candidates also spent the longest time on dialysis before waitlisting, regardless of clinical outcome, at a median of 1075 (IQR, 422–2049) days compared with 263 (IQR, 121–547) days for pediatric + OD and 305 (IQR, 156–611) days for YA + OD ≥ 18 candidates (P <.001).¹

In multivariable analysis, compared with pediatric-NYOD recipients, YA + OD < 18 recipients had a 55.0% increased risk of graft loss at 3 years (Hazard ratio [HR], 1.550; 95% CI, 1.196–1.918; P <.001) and a 47.7% increased risk of graft loss at 5 years (HR, 1.477; 95% CI, 1.218–1.792; P <.001).¹

“The findings reported here support the need to re-examine and revise current allocation policies for YAs to increase access to high-quality grafts and ensure equity across this young and vulnerable patient population,” investigators concluded.¹

References

1. ^{Steggerda JA, Wisel SA, Puliyanda D, et al. Pediatric Age-Prioritized Waitlisting Policy Potentially Disadvantages Adolescents on Dialysis Not Listed for Transplant Until Adulthood. Pediatric Transplantation. https://doi.org/10.1111/petr.70023}
2. ^{OPTN. Kidney allocation system. Accessed January 28, 2025. https://optn.transplant.hrsa.gov/professionals/by-organ/kidney-pancreas/kidney-allocation-system/}