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Recent changes to U.S. donor heart allocation were followed by a narrowing of racial disparities in listing and transplant, though much more work remains to eliminate inequality, researchers warned.

Black patients listed for cardiac transplantation in 2011-2020 were less likely than white peers to die while waiting (adjusted HR 0.88, 95% CI 0.78-0.98). However, they ultimately had lower odds of undergoing transplant (adjusted HR 0.87, 95% CI 0.84-0.90) and a higher risk of post-transplant death (adjusted HR 1.14, 95% CI 1.04-1.24), reported P. Elliott Miller, MD, of Yale School of Medicine in New Haven, Connecticut, and colleagues.

Importantly, the 2018 United Network for Organ Sharing (UNOS) allocation system change marked an inflection point during the decade: following this change, median waitlist times were halved or better in all racial and ethnic groups, and transplantation rates increased for all.

Nevertheless, Black patients still had a lower likelihood of transplantation compared with white patients (adjusted HR 0.90, 95% CI 0.79-0.99), they said.

There were no differences in transplantation likelihood or post-transplant mortality between Hispanic and white patients during the study period.

Contributing factors to racial disparities include immunologic or genetic mismatch between heart donors and recipients. As in the case of many reported health disparities, social determinants of health may also play a large part in the observed disparities in cardiac transplantation.

In 2018, the UNOS revised their allocation system from three to six tiers "to expand access to organs for the most medically urgent patients, and reduce disparities as well as regional differences," Miller and colleagues explained. "The older geographic sharing methodology created longer wait times for patients in diverse, highly populated regions, potentially affecting minority recipients more."

However, the new six-tier system has been associated with unintended consequences, as centers learn to game the rules.

The study authors advocated for more organ allocation interventions to improve equality, as well as larger societal policy changes to narrow the racial gap in overall cardiovascular disease outcomes.

"Prevention of end-stage HF [heart failure] with equitable risk factor reduction and use of guideline-directed HF therapies remains a priority," wrote Sabra Lewsey, MD, MPH, of Johns Hopkins University School of Medicine in Baltimore, and Khadijah Breathett, MD, MS, of the University of Arizona's Sarver Heart Center in Tucson, in an .

As for equity in donor heart allocation, Lewsey and Breathett suggested targeting the financial aspects of transplantation.

"As HT [heart transplantation] is a life-saving, but expensive endeavor, individuals without insurance are unable to be considered. Expansion of insurance coverage must be a primary consideration in improving equitable access to transplantation in diverse communities," the editorialists noted.

"Previous calls for reform in financial considerations of HT are decisively still warranted. Adequacy of posttransplant insurance must be paired with these reforms. Reconsideration of end-stage HF as a condition warranting Medicare coverage regardless of age may be central to equitable access," they continued.

Finally, each center should have its heart transplant committee considerations reviewed for objectivity, transparency, and bias, Lewsey and Breathett suggested.

Miller's team performed a retrospective review of UNOS registry data, including 32,353 U.S. adults; 25% identified as Black, 9% identified as Hispanic, and 66% identified as white.

Compared with white patients on the waitlist, Black and Hispanic patients were a few years younger, more likely to be women, and more likely to have diabetes or renal disease.

Among all listed patients, the proportion of Black and Hispanic patients increased significantly, from 21.7% and 7.7%, respectively, in 2011 to 28.2% and 9.0% in 2020. Among all transplanted patients, Black patients saw their share rise from 20.8% to 27.3%, while Hispanic peers dipped from 8.5% to 8.4%.

A supplementary analysis of Asian patients found that this group had higher odds of transplantation than white patients (adjusted HR 1.38, 95% CI 1.28-1.48), with no difference in waitlist death or post-transplant death.

Given its reliance on the UNOS database, the study failed to capture all patients living with advanced heart failure who may be candidates for heart transplantation, Miller and colleagues acknowledged.

In addition, they said, the allocation policy is still relatively new and local practices continue to evolve under the new system. "In particular, the impact of the COVID-19 pandemic on heart transplantation from 2020 remains incompletely understood, and likely resulted in atypical patterns of care," the authors cautioned.

"Overall, these findings suggest that the new allocation system may be narrowing previously noted racial disparities in cardiac transplantation, but additional investigation is required to better understand and address continued disparities," Miller's group concluded.

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