Kidney Donor Profile Index Does Not Accurately Predict the Graft Survival of Pediatric Deceased Donor Kidneys

Abstract

Background The new deceased donor kidney allocation algorithm uses a Kidney Donor Profile Index (KDPI) based on donor characteristics to predict graft survival and divides kidneys into 4 quality groups (i.e., KDPI-A, -B, -C, and -D). Pediatric kidneys constitute 10–12% of deceased donor kidneys. We hypothesized that KDPI would not accurately predict pediatric donor graft survival and superior predictive models could be created. Methods Scientific Registry of Transplant Recipients data for years 2000–2010 for transplants from child (<10 years) and adolescent (10–17 years inclusive) donors into first-time adult recipients were analyzed with graft failure as the principle outcome. Two novel indices, Child Donor Index (CDI) and Adolescent Donor Index (ADI), were developed using stepwise variable deletion to identify significant model covariates in a Cox Regression. Pediatric donor kidneys were then classified into the four quality groups based on both KDPI and CDI/ADI scores. The performance of the KDPI, CDI and ADI models were compared with respect to the four quality groups defined by the new allocation system. Results KDPI did not effectively discriminate between quality groups (p> 0.05 for all but one comparison) in Kaplan-Meier survival analyses. CDI and ADI included novel variables (e.g., body mass index percentiles) and successfully discriminated between quality groups (p<0.05 by log rank test). The Net Reclassification Index showed improvement when switching from KDPI to CDI and ADI, with values of 0.09 (p<0.001) and 0.073 (p<0.001) respectively. Conclusion KDPI does not accurately predict pediatric kidney graft survival. Alternative indices can improve allocation efficiency.

Decreasing deceased donor transplant rates among children (≤6 years) under the new kidney allocation system

“…Beyond discard, Nazarian et al noted a significant decrease in the proportion of pediatric donors transplanted into pediatric recipients post‐KAS as compared to pre‐KAS, suggesting that the donor pool available to children has been restricted post‐KAS to exclude many pediatric donors due to KDPI . Moreover, allocation of pediatric donors based upon KDPI is likely flawed as KDPI has been shown to be a poor predictor of graft outcomes among pediatric donors . Considering the high mortality rates on dialysis and the deleterious effect of prolonged dialysis duration on growth and development among these young pediatric registrants, further monitoring of DDKT rates in this population is warranted to guarantee DDKT rates are not further eroded …”

Characteristics of compatible pair participants in kidney paired donation at a single center

“…Despite its limitations, however, the LKDPI can serve as an objective starting point when patients and transplant centers seek to assess the potential benefits of CPP in KPD . Among recipients of deceased donor kidney transplants, OPTN already mandates that transplant centers inform and consent recipients if the donor has a kidney donor profile index (KDPI) >85%, despite the known limitations of the KDPI . In the future, transplant centers may consider discussing the LKDPI with compatible pairs who participate in KPD.…”

The kidney allocation system does not appropriately stratify risk of pediatric donor kidneys: Implications for pediatric recipients

“…While an elegant solution might be to adopt a KDPI validated for pediatric donors as suggested by Parker et al, (17) such implementation through UNOS is likely to be logistically complex. Until such time, we suggest that pediatric donors be offered first to pediatric recipients, without KDPI restriction and at the typical allocation sequence for pediatric priority, allowing pediatric centers to appropriately risk stratify the possible advantages or disadvantages of pediatric donor kidneys for their own patients.…”