Introduction: In 2018, a new heart allocation policy was implemented to promote uniform access to transplantation by mandating sharing of donor hearts over larger geographic areas rather than by location within a given Donation Service Area (DSA). The long-term impact of this policy on sharing across DSAs is unknown. Methods: Using data from the Scientific Registry of Transplant Recipients, we assessed the association between the new policy and organ sharing at the level of each DSA. We included adult, single-organ heart transplants performed in the mainland US between Oct 1, 2015 and Dec 31, 2020. For each DSA, we evaluated the proportion of donor hearts imported from another DSA, the proportion exported, and their log-transformed ratio (sharing ratio). We performed multivariable regression with heteroscedasticity to evaluate the association between policy period and sharing ratio, adjusting for deaths per DSA population, household income and urbanicity. Results: The new policy was associated with increased importation and exportation of donor hearts across DSAs (Figure). The mean import proportion increased from 0.31 (95% CI: 0.27 to 0.36) to 0.74 (95% CI: 0.71 to 0.78) and the mean export proportion from 0.36 (95% CI: 0.31 to 0.40) to 0.75 (95% CI: 0.71 to 0.79) after the policy change. In addition, the mean sharing ratio of import:export shifted from 1.22 (95% CI: 0.91 to 1.53) to 1.01 (95% CI: 0.96 to 1.07) suggesting more balance across DSAs. The variance of the log-transformed sharing ratio was negatively associated with the new policy (β = -1.55; 95% CI, -1.82 to -1.27; P < .001), indicating a 79% drop in the variation of the sharing ratio and more uniform access. Deaths per DSA population was associated with the log-transformed sharing ratio while household income and urbanicity were not. Conclusion: The new policy is associated with more balanced sharing of hearts. The broader impact on waitlist survival and post-transplant outcomes remains unknown.
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