Between-center variation in high-priority listing status under the new heart allocation policy

Abstract

Under the new US heart allocation policy, transplant centers listed significantly more candidates at high priority statuses (Status 1 and 2) with mechanical circulatory support devices than expected. We determined whether the practice change was widespread or concentrated among certain transplant centers. Using data from the Scientific Registry of Transplant Recipients, we used mixed-effect logistic regression to compare the observed listings of adult, heart-alone transplant candidates post-policy (December 2018 to February 2020) to seasonally matched pre-policy cohort (December 2016 to February 2018). US transplant centers (N = 96) listed similar number of candidates in each policy period (4472 vs. 4498) but listed significantly more at high priority status (25.5% vs. 7.0%, p < .001) than expected. Adjusted for candidate characteristics, 91 of 96 (94.8%) centers listed significantly more candidates at high-priority status than expected, with the unexpected increase varying from 4.8% to 50.4% (interquartile range [IQR]: 14.0%-23.3%). Centers in OPOs with highest Status 1A transplant rate pre-policy were significantly more likely to utilize high-priority status under the new policy (OR: 9.73, p = .01). The new heart allocation policy was associated with widespread and significantly variable changes in transplant center practice that may undermine the effectiveness of the new system.

Keywords: cardiology; ethics; heart transplantation; organ Procurement and Transplantation Network (OPTN); organ allocation; public policy.

FIGURE 1

(A) Trends in expected and observed priority statuses during transition to the new heart allocation policy. Trends in the number of adult heart transplant candidates listed each month, as stratified by Status at initial listing. Colors correspond with observed status assignment in the post-policy period (after October 2018), and reclassified expected status assignment in the pre-policy period (before October 2018). Status 5 is for multiorgan transplant candidates, which were excluded from the analyses. Dashed line represents October 2018, when the new allocation policy was implemented. (B) Trends in high-priority status MCS justifications and exceptions during transition to the new heart allocation policy. Trends in the number of adult heart transplant candidates listed at high-priority statuses in each month, as stratified by treatment at initial listing. Prior to the implementation of the new allocation policy in October 2018, colors correspond to the treatments candidates reclassified as Status 1 and 2 or qualified for Status 1A through exception requests. After October 2018, colors correspond to the treatments used to justify Status 1 and Status 2 listings. Dashed line represents October 2018, when the new allocation policy was implemented. ECMO, extracorporeal membrane oxygenation; IABP, intra-aortic balloon pump; LVAD, left ventricular assistive device (with device malfunction to qualify for Status 1 or 2); Other MCS, other mechanical circulatory support

FIGURE 2

Between-center variation in high-priority status listing after implementation of the new heart allocation policy. Caterpillar plot showing the estimated probability of being listed at high-priority (Status 1 or Status 2) at each transplant center, adjusting for candidate characteristics. Colors correspond to the predicted rate of being listed in high-priority status based on status reclassification of pre-policy candidates (green) and the rate based on observed utilization of high-priority statuses after the policy change (red). The expected rates (green) represent the counterfactual scenario in which center practices did not change in response to the new heart allocation policy. The 95% CIs were constructed via bootstrapping. Transplant centers were ranked based on predicted probability of high-priority listing after policy update. Asterisks indicate centers with statistically significant change in the estimated probability of listing in Status 1 or 2 before and after implementing the new policy. The observed rate significantly exceeded the expected rate in 91 out of 96 centers (94.8%)

FIGURE 3

Geographical variation in high-priority status listing after implementation of the new heart allocation policy. National variation in the rate of being listed at high priority (Status 1 or Status 2), estimated from multilevel logistic regression model adjusted for candidate level characteristics. Rates are aggregated at the Organ Procurement Organization (OPO) level, the first local level of organ allocation in the United States. Colors correspond to the estimated probability the average candidate is listed at high priority status (Status 1 or 2). Map on the left displays the expected rate of high-priority listing in each OPO, generated from applying the new allocation scheme to candidates listed between December 2016 and February 2018. Map on the right displays the case-mix adjusted rates of Status 1 and 2 listing observed at each OPO from December 2018 to February 2020, after the new allocation scheme was implemented