Early effects of acuity circle-based liver allocation during COVID-19 pandemic in the United States

ABSTRACT

Purpose: One month before the COVID-19 pandemic was declared, liver transplant (LT) allocation in the US was updated (February 4th, 2020), by introducing the acuity circle (AC)-based model. This study evaluated the early effects of the AC-based allocation on waitlist outcomes. Methods: Adult candidates listed between January 1st, 2019, and June 30th, 2020, were evaluated. Two periods were defined according to the listing date (pre- and post-AC), and 90-day waitlist outcomes were compared. Data was censored if none of the events had occurred before the end of the period. The median transplant MELD score of each state was calculated, and states were defined as low-(<25th%ile), mid- (25th-75th%ile), and high-(>75th%ile) MELD regions. In addition, transplanted patients were categorized into 3 groups according to their final MELD score (6-14, 15-28, 29+). Organ sharing and donor characteristics were compared between eras. Results: 12,546 and 3,932 candidates in pre and post-AC eras were eligible. The post-AC era was associated with significantly lower 90-day waitlist mortality (HR=0.75, 95%CI=0.62-0.90;p=0.002) and higher transplant probability (HR=1.19, 95%CI=1.10-1.29;p<0.001). When outcomes were assessed in each MELD region group, improvement in outcomes was significant in mid-MELD regions, but not in other MELD regions. Among 5,971 and 772 transplanted in the pre and post- AC eras, national sharing significantly increased in all groups (overall 7.4% to 32.5%, P<0.001). In contrast, a significant increase and decrease in the proportion of donation-after-circulatory-death (DCD)-LT was observed in the low- and mid- MELD regions, respectively. Another subgroup analysis showed that national sharing significantly increased in those with a score of 15-28 (7.6% to 22.1%, P<0.001) and 29+ (5.0% to 39.6%, P<0.001), but not in those with score of 6-14 (15.7% to 22.7%, P=0.11). Patients with a MELD score 15-28 received DCD-LT more frequently in post-AC era, but not in those with a score of 29+. (Table). Conclusions: Despite the COVID-19 pandemic, AC-based allocation improved waitlist outcomes in mid-MELD regions. While other regions had comparable out comes, aggressive utilization of DCD might offset possible negative effects of the AC-based model and/or pandemic in low-MELD regions. Organ acceptance practice may be significantly changed in certain regions/patient populations such as DCD acceptance for patients with mid MELD score in lower MELD regions. It is crucial to carefully monitor possible effects of those changes on post-transplant outcomes. (Table Presented).