Longitudinal analysis of living donor kidney transplant rates in pediatric candidates in the United States

Transition of young adult kidney transplant recipients

Survival of pediatric kidney transplant recipients has improved over the past six decades. However, adolescents and young adults still have the highest graft failure rates of any age group. There is a growing need for well-designed transition programs to ensure the successful integration of young adults into adult society with eventual transfer of care and management in adult transplant centers. In this review, we discuss the risk factors contributing to the high risk of kidney graft failure observed between 17 and 24 years of age, including the role of transfer from pediatric to adult care. We also address the unique challenges of adolescents with kidney transplant: the impact of chronic kidney disease on neurocognition, age-related changes in immune activity, and suboptimal adherence during the transition process. We then describe strategies to mitigate these risks by designing developmentally appropriate transition programs, and review the evidence supporting the benefits of well-designed multidisciplinary transition programs.

Long-Term Care of the Pediatric Kidney Transplant Recipient

Pediatric kidney transplant recipients are distinguished from adult recipients by the need for many decades of graft function, the potential effect of CKD on neurodevelopment, and the changing immune environment of a developing human. The entire life of an individual who receives a transplant as a child is colored by their status as a transplant recipient. Not only must these young recipients negotiate all of the usual challenges of emerging adulthood (transition from school to work, romantic relationships, achieving independence from parents), but they must learn to manage a life-threatening medical condition independently. Regardless of the age at transplantation, graft failure rates are higher during adolescence and young adulthood than at any other age. All pediatric transplant recipients must pass through this high-risk period. Factors contributing to the high graft failure rates in this period include poor adherence to treatment, potentially exacerbated by the transfer of care from pediatric- to adult-oriented care providers, and perhaps an increased potency of the immune response. We describe the characteristics of pediatric kidney transplant recipients, particularly those factors that may influence their care throughout their lives. We also discuss the risks associated with the transition from pediatric- to adult-oriented care and provide some suggestions to optimize the transition to adult-oriented transplant care and long-term outcomes.

Donor considerations in pediatric kidney transplantation

This article reviews kidney transplant donor options for children with end-stage kidney disease (ESKD). Global access to kidney transplantation is variable. Well-established national policies, organizations for organ procurement and allocation, and donor management policies may account for higher deceased donor (DD transplants) in some countries. Living donor kidney transplantation (LD) predominates in countries where organ donation has limited national priority. In addition, social, cultural, religious and medical factors play a major role in both LD and DD kidney transplant donation. Most children with ESKD receive adult-sized kidneys. The transplanted kidney has a finite survival and the expectation is that children who require renal replacement therapy from early childhood will probably have 2 or 3 kidney transplants in their lifetime. LD transplant provides better long-term graft survival and is a better option for children. When a living related donor is incompatible with the intended recipient, paired kidney exchange with a compatible unrelated donor may be considered. When the choice is a DD kidney, the decision-making process in accepting a donor offer requires careful consideration of donor history, kidney donor profile index, HLA matching, cold ischemia time, and recipient's time on the waiting list. Accepting or declining a DD offer in a timely manner can be challenging when there are undesirable facts in the donor's history which need to be balanced against prolonging dialysis in a child. An ongoing global challenge is the significant gap between organ supply and demand, which has increased the need to improve organ preservation techniques and awareness for organ donation.

Time to second kidney transplantation in young adults after failed pediatric kidney transplant

BACKGROUND

Under the current kidney allocation system, pediatric candidates listed prior to age 18 receive priority for high-quality deceased donor organs. This has resulted in a decline in living donor transplantation in pediatrics, despite superior outcomes of living donor transplantation. Due to a young age at transplantation, most pediatric kidney transplant recipients require re-transplantation. The effects of a previously failed deceased donor vs a previously failed living donor on re-transplant candidates are unknown.

METHODS

Using the United Network for Organ Sharing database, we examined 2772 re-transplant recipients aged 18-30 years at time of relisting for second KT from 2000 to 2018 with history of prior pediatric KT (age ≤ 18 years).

RESULTS

PFLDKT recipients compared to those with PFDDKT had shorter median waiting times and dialysis time regardless of their second donor type (14.0 vs 20.3 months, and 19.1 vs 34.5 months, respectively). PFLDKT recipients had higher re-transplant rates (adjusted HR 1.17, 95% CI 1.09-1.27, and adjusted HR 1.05, 95% CI 0.95-1.15 when calculating from time of relisting and time of returning to dialysis, respectively). PFDDKT recipients were more likely to have higher median PRA levels (90% vs 73%).

CONCLUSIONS

Re-transplant candidates who received a previous deceased donor as a child had a higher level of sensitization, longer waiting time, and dialysis exposure compared to those with PFLDKT. Among primary pediatric kidney transplant candidates, consideration should be considered for living donor transplantation, despite the priority for deceased donor organs, to avoid increased sensitization and longer waiting times for with re-transplantation.

Trends in Living Donation by Race and Ethnicity Among Children With End-stage Renal Disease in the United States, 1995-2015

BACKGROUND

Living donor kidney transplants have declined among adults with end-stage renal disease (ESRD), with increases in racial/ethnic disparities over time. Secular trends in racial/ethnic disparities in living donor kidney transplantation have not been well studied in children.

METHODS

Using multivariable Cox modeling, we examined changes in living donor kidney transplant rates over time and probability of receiving living donor kidney transplantation within 2 years of incident ESRD by race/ethnicity among 19 772 children in the US Renal Data System, 1995-2015. We also examined racial/ethnic concordance between donors and recipients.

RESULTS

Overall, living donor kidney transplant rates declined by 3% annually since 1995 for all racial/ethnic groups except Asians for whom living donor kidney transplant rates remained stable; however, disparities persist. Compared with non-Hispanic white children, Hispanics were 42% less likely (adjusted hazard ratio: 0.58; 95% confidence interval: 0.49-0.67), Asians 39% less likely (0.61; 0.47-0.79), and blacks 66% less likely (0.34; 0.28-0.42) to receive living kidney donor transplantation within 2 years, even when accounting for deceased donor transplantation as a competing risk. Additionally, while 95% of non-Hispanic white children had non-Hispanic white donors, only 56% of Asian recipients had Asian donors (P < 0.001). Asian recipients were more likely to have nonrelated donors (P < 0.001).

CONCLUSIONS

There are ongoing declines in living donation for children with ESRD for uncertain reasons, and minority populations experience significantly reduced access to timely living donor transplant, even when accounting for changes in deceased donation and donor-recipient relationships.

Renal allograft loss due to renal vascular thrombosis in the US pediatric renal transplantation

BACKGROUND

Renal vascular thrombosis (RVT) is a major cause of early allograft loss in the first year following pediatric kidney transplantation. We examined recent trends in allograft loss due to RVT and identified associated risk factors.

METHODS

We identified 14,640 kidney-only transplants performed between 1995 and 2014 with follow-up until June 30, 2016, in 13,758 pediatric patients aged < 19 years from the US Renal Data System. We examined the 1-year incidence of allograft loss due to RVT by year of transplant, and plotted the trend over time. Cox proportional hazards models were used to investigate the relationship between year of transplant as well as recipient, donor, and transplant characteristics with allograft loss due to RVT.

RESULTS

The incidence of allograft loss due to RVT consistently declined among pediatric kidney transplant performed between 1995 and 2014. Among transplants performed between 1995 and 2004, 128/7542 (1.7%) allografts were lost due to RVT compared to 53/7098 (0.8%) among transplants performed between 2005 and 2014; average 1-year cumulative incidence was 1.5% (95% CI, 1.3-1.9%) and 0.6% (95% CI, 0.5-0.8%), respectively. Increased risk for allograft loss due to RVT was associated with en bloc kidney transplantation (HR, 3.42; 95% CI 1.38-8.43) and cold ischemia time ≥ 12 h (HR, 1.78; 95% CI, 1.15-2.76). Interestingly, these risk factors were more prevalent in the latter decade.

CONCLUSIONS

The incidence of allograft loss due to RVT significantly and continuously declined among pediatric kidney transplants performed between 1995 and 2014. The causes for this improvement are unclear in the present analysis.

Long-Term Outcomes of Kidney Transplantation in Children

Kidney transplantation is the preferred treatment for end-stage renal disease (ESRD) in children and confers improved survival, skeletal growth, heath-related quality of life, and neuropsychological development compared with dialysis. Kidney transplantation in children with ESRD results in 10-year patient survival exceeding 90%. Therefore, the long-term management of these patients is focused on maintaining quality of life and minimizing long-term side effects of immunosuppression. Optimal management of pediatric kidney transplant recipients includes preventing rejection and infection, identifying and reducing the cardiovascular and metabolic effects of long-term immunosuppressive therapy, supporting normal growth and development, and managing a smooth transition into adulthood.

The choice between deceased- vs living-donor renal transplantation in children: Analysis of data from a Belgian tertiary center

Pediatric renal transplantation with a living donor (LD) has superior outcome, but there is a paucity of studies analyzing the reasons for not undertaking living donation in West-European countries. The aim of this study was to retrospectively review the choice of donor source in our center. We also aimed to identify factors which prevented transplantation with a LD. This retrospective study was performed including children aged 2-19 years who underwent kidney transplantation (KT) at the Ghent University Hospital between 1996 and 2016. Relevant data were collected from medical files to identify the main medical, psychological, and socio-economic factors influencing the choice of the donor source. There were 48 patients (boys n = 33) who underwent KT. Thirty-nine patients received a deceased donor (DD) kidney and nine patients received a LD kidney. Sixteen of 48 transplantations were preemptive. The reasons for DD KT included socio-economic factors such as single caregiver families, one or both parents with a criminal record or convictions and religious or cultural constraints (n = 15), medical considerations (n = 13), refusal of the close relatives/parents to donate (n = 7), and acceptance of an organ from a DD while prospective donor was undergoing medical screening (n = 4). The low incidence of living kidney donation can be explained by socio-economic and medical factors. Refusal to donate is a potentially modifiable factor and strategies aimed at education and guidance of the families might contribute to a higher incidence of living donation in our setting.

Application and interpretation of histocompatibility data in pediatric kidney transplantation

PURPOSE OF REVIEW

Advances in technology to assess immunologic risk in solid organ transplant offer an opportunity to optimize the approach to pediatric deceased donor kidney transplant in the setting of a new allocation system in the United States.

RECENT FINDINGS

Degree of human leukocyte antigen (HLA) mismatch, class II HLA mismatch, unacceptable antigens and donor-specific antibody (DSA) detected by solid-phase assays, and epitope matching pretransplant affect pediatric kidney transplant outcomes. Detection of de novo DSAs (dnDSAs) posttransplant has been associated with increased risk of acute rejection and worse allograft function. Development of dnDSA occurs in recipients with greater epitope mismatching.

SUMMARY

Improved long-term outcomes may be anticipated in pediatric kidney transplant recipients by incorporating extended HLA mismatch information and updating the clinical approach to donor kidney matching using available technology to identify clinically relevant immunologic risk.