Relationships between 2018 UNOS heart policy and transplant outcomes in metropolitan, micropolitan, and rural...

In 2018, United Network for Organ Sharing (UNOS) extended the radius for which a heart transplant candidate can match with a donor, and outcomes across population densities are unknown. We sought to determine whether the policy change was associated with differences in heart transplant waitlist time or death post-transplant for patients from rural, micropolitan, and metropolitan settings.

Using the Scientific Registry of Transplant Recipients, we evaluated U.S. adult patients listed for heart transplant from Janurary 2017 to September 2019 with follow-up through March 2020. Patients were stratified by home zip-codes to either metropolitan, micropolitan, or rural settings. Fine and Gray and Cox models were respectively used to estimate Sub-distribution hazard ratios (SHR) of heart transplant with death or removal from transplant list as a competing event, and HR of death post-transplant within population densities after versus before the UNOS policy change date, October 18, 2018. Analyses were adjusted for demographics, comorbidities, and labs.

Among 8,747 patients listed for heart transplant, 84.7% were from metropolitan, 8.6% micropolitan, and 6.6% rural settings. The 2018 UNOS policy was associated with earlier receipt of heart transplant for metropolitan [SHR 1.56 (95% CI: 1.46-1.66)] and micropolitan [SHR 1.48 (95% CI: 1.21-1.82)] populations, but not significantly for rural [SHR 1.20 (95% CI: 0.93-1.54)]; however, the interaction between policy and densities was not significant (p = .14). Policy changes were not associated with risk of death post-transplant [metropolitan: HR 1.04 (95% CI: 0.80-1.34); micropolitan: HR 1.10 (95% CI: 0.55-2.23); rural: HR 1.04 (95% CI: 0.52-2.08); interaction p = .99].

The 2018 UNOS heart transplant policy was associated with earlier receipt of heart transplant and no difference in post-transplant survival within population densities. Additional follow-up is needed to determine whether improvements are sustained.