Impact of Acuity Circles on Outcomes for Pediatric Liver Transplant Candidates

Abstract

Background. In December 2018, United Network for Organ Sharing approved an allocation scheme based on recipients’ geographic distance from a deceased donor (acuity circles [ACs]). Previous analyses suggested that ACs would reduce waitlist mortality overall, but their impact on pediatric subgroups was not considered. Methods. We applied Scientific Registry of Transplant Recipients data from 2011 to 2016 toward the Liver Simulated Allocation Model to compare outcomes by age and illness severity for the United Network for Organ Sharing–approved AC and the existing donor service area–/region-based allocation schemes. Means from each allocation scheme were compared using matched-pairs t tests. Results. During a 3-year period, AC allocation is projected to decrease waitlist deaths in infants (39 versus 55; P < 0.001), children (32 versus 50; P < 0.001), and teenagers (15 versus 25; P < 0.001). AC allocation would increase the number of transplants in infants (707 versus 560; P < 0.001), children (677 versus 547; P < 0.001), and teenagers (404 versus 248; P < 0.001). AC allocation led to decreased median pediatric end-stage liver disease/model for end-stage liver disease at transplant for infants (29 versus 30; P = 0.01), children (26 versus 29; P < 0.001), and teenagers (26 versus 31; P < 0.001). Additionally, AC allocation would lead to fewer transplants in status 1B in children (97 versus 103; P = 0.006) but not infants or teenagers. With AC allocation, 77% of pediatric donor organs would be allocated to pediatric candidates, compared to only 46% in donor service area–/region-based allocation (P < 0.001). Conclusions. AC allocation will likely address disparities for pediatric liver transplant candidates and recipients by increasing transplants and decreasing waitlist mortality. It is more consistent with federally mandated requirements for organ allocation.

A Review of the Current State of Liver Transplantation Disparities

“…In addition, many pediatric livers ended up being transplanted into adults, suggesting that the allocation algorithm did not prioritize children enough. ( 68,69 ) Pediatric liver candidates are at a unique disadvantage in the transplant allocation process because of the difficulty finding appropriately sized grafts. ( 68,70 ) There are also data suggesting that the Pediatric End‐Stage Liver Disease (PELD) score may underestimate 90‐day mortality and thus put pediatric transplant candidates at a disadvantage while on the waiting list compared with adults.…”

“…( 68,70,82 ) One study simulating the effect of the newly implemented acuity circles allocation scheme found that the new UNOS policy will likely decrease waitlist deaths in pediatric recipients and result in more pediatric grafts being allocated to pediatric recipients rather than adult recipients. ( 69 ) In the adult literature, age matching and age mapping are 2 of the more well‐studied equity principles, both of which match organ recipients to donors of a similar age with the theory that younger (and thus better) organs should be prioritized to younger recipients. ( 83,84 ) A retrospective analysis of liver transplants performed at 2 Italian centers found that age mapping would have decreased the gap in the years of lives lost between the youngest and oldest adult recipient age groups by about 33%, ( 83 ) but data are lacking on the effect that age mapping would have on the pediatric population.…”

Liver transplantation in the United States during the COVID-19 pandemic: National and center-level responses

“…Based on simulated models, the acuity circles allocation is expected to decrease waitlist deaths and geographic variation in MELD at transplant, and increase the overall number of DDLTs. 28,29 The expected values from February 1, 2016 to January 31, 2020 represent a counterfactual for what would have happened from February 1, 2020 to September 2, 2020 without the effects of either the COVID-19 pandemic or the acuity circles policy change. It is striking to see that despite the policy change, there is a decrease in the number of DDLTs.…”

Implementing a Height‐Based Rule for the Allocation of Pediatric Donor Livers to Adults: A Liver Simulated Allocation Model Study

“…Fortunately, our height-based rule was applied after pediatric candidates were exhausted to avoid harm to children, who were disadvantaged under region-based allocation. (5) There are several limitations to this analysis. The SRTR data were from 2013 through 2016.…”