Greater geographic sharing and heart transplantation waitlist outcomes following the 2018 heart allocation policy

Abstract

In 2018, a new heart allocation policy was introduced to reduce variability in access to and outcomes after transplantation, in part, through attempts at broader geographic sharing of donor hearts. We evaluated how this policy affected geographic sharing and waitlist outcomes by donation service area (DSA). This retrospective study of the Scientific Registry of Transplant Recipients database included adult patients waitlisted between October 2016 and October 2020, stratified by policy period. Our primary outcomes were mean proportion of imported and exported hearts aggregated by DSA as well as time to transplant. Following the policy change, there was substantial evidence of sharing across DSAs. The mean proportion of imported hearts transplanted by a DSA increased from 32% (95% CI: 27%-36%) to 74% (95% CI: 71%-78%; p < 0.001), and the mean proportion of exported hearts increased from 37% (95% CI: 33%-42%) to 75% (95% CI: 71%-79%; p < 0.001). The mean sharing ratio, defined as the log-transformed ratio of imported to exported hearts per DSA, shifted from 1.15 (95% CI: 0.88-1.42) to 1.02 (95% CI: 0.96-1.07), with a 76% decline in the variance across DSAs. As sharing increased, time to transplant per DSA declined from 153.9 days (95% CI, 143.4-164.4 days) pre-policy to 89.6 days (95% CI, 83.1-96.1 days) post-policy (p < 0.001). A larger decrease in waitlist time was associated with a higher proportion of exported hearts. The 2018 heart allocation policy was associated with more uniform access to heart transplantation and improved waitlist outcomes.