Racial disparities in cardiac transplantation: Chronological perspective and outcomes

Racial and Ethnic Disparities in Peri-and Post-operative Cardiac Surgery

Purpose of Review

Despite efforts to curtail its impact on medical care, race remains a powerful risk factor for morbidity and mortality following cardiac surgery. While patients from racial and ethnic minority groups are underrepresented in cardiac surgery, they experience a disproportionally elevated number of adverse outcomes following various cardiac surgical procedures. This review provides a summary of existing literature highlighting disparities in coronary artery bypass surgery, valvular surgery, cardiac transplantation, and mechanical circulatory support.

Recent Findings

Unfortunately, specific causes of these disparities can be difficult to identify, even in large, multicenter studies, due to the complex relationship between race and post-operative outcomes. Current data suggest that these racial/ethnic disparities can be attributed to a combination of patient, socioeconomic, and hospital setting characteristics.

Summary

Proposed solutions to combat the mechanisms underlying the observed disparate outcomes require deployment of a multidisciplinary team of cardiologists, anesthesiologists, cardiac surgeons, and experts in health care equity and medical ethics. Successful identification of at-risk populations and the implementation of preventive measures are necessary first steps towards dismantling racial/ethnic differences in cardiac surgery outcomes.

Racial and ethnic disparities in heart transplantation for end-stage heart failure: An analysis of the national inpatient sample (NIS) database

PURPOSE

This study aims to examine disparities among heart transplant recipients in the United States, utilizing the latest data from the National Inpatient Sample (NIS).

METHODS

We conducted a retrospective cohort analysis of NIS discharge data (2017-2020), focusing on adult end-stage heart failure (ESHF) patients, identified using the ICD-10 CM code I50.84. Our analysis included four racial groups: White, Black, Hispanic, and Asian. We employed univariable and multivariate regression analyses to determine the unadjusted and adjusted odds of heart transplantation across these racial groups, using Stata version 14.2 for statistical calculations.

RESULTS

Of 110,015 ESHF patients, 3,695 received heart transplants. Predominantly, recipients were male with a Charlson comorbidity index ≥3 and covered by private insurance. Transplants mainly occurred in large, teaching hospitals. Despite minor differences in age and median household income among races, baseline patient and hospital characteristics showed no significant variations. Compared to Whites, Blacks had a significantly lower transplant rate (AOR: 0.6; 95  % CI: 0.46-0.77; p < 0.001), while Hispanics and Asians showed no significant disparities. Mean ages varied slightly across groups (p = 0.0047), yet inpatient length of stay and hospitalization costs did not significantly differ.

CONCLUSION

Our findings highlight a significant disparity in heart transplant rates between Black and White ESHF patients in the U.S., with Black patients less likely to receive transplants compared to their White counterparts.

Paving a Path to Equity in Cardiorenal Care

Cardiorenal syndrome encompasses a dynamic interplay between cardiovascular and kidney disease, and its prevention requires careful examination of multiple predisposing underlying conditions. The unequal distribution of diabetes, heart failure, hypertension, and kidney disease requires special attention because of the influence of these conditions on cardiorenal disease. Despite growing evidence regarding the benefits of disease-modifying agents (e.g., sodium-glucose cotransporter 2 inhibitors) for cardiovascular, kidney, and metabolic (CKM) disease, significant disparities remain in access to and utilization of these essential therapeutics. Multilevel barriers impeding their use require multisector interventions that address patient, provider, and health system-tailored strategies. Burgeoning literature also describes the critical role of unequal social determinants of health, or the sociopolitical contexts in which people live and work, in cardiorenal risk factors, including heart failure, diabetes, and chronic kidney disease. This review outlines (i) inequality in the burden and treatment of hypertension, type 2 diabetes, and heart failure; (ii) disparities in the use of key disease-modifying therapies for CKM diseases; and (iii) multilevel barriers and solutions to achieve greater pharmacoequity in the use of disease-modifying therapies. In addition, this review provides summative evidence regarding the role of unequal social determinants of health in cardiorenal health disparities, further outlining potential considerations for future research and intervention. As proposed in the 2023 American Heart Association presidential advisory on CKM health, a paradigm shift will be needed to achieve cardiorenal health equity. Through a deeper understanding of CKM health and a commitment to equity in the prevention, detection, and treatment of CKM disease, we can achieve this critical goal.

Disparities by Sex, Race, and Ethnicity in Use of Left Ventricular Assist Devices and Heart Transplants Among Patients With Heart Failure With Reduced Ejection Fraction

BACKGROUND

The extent to which sex, racial, and ethnic groups receive advanced heart therapies equitably is unclear. We estimated the population rate of left ventricular assist device (LVAD) and heart transplant (HT) use among (non-Hispanic) White, Hispanic, and (non-Hispanic) Black men and women who have heart failure with reduced ejection fraction (HFrEF).

METHODS AND RESULTS

We used a retrospective cohort design combining counts of LVAD and HT procedures from 19 state inpatient discharge databases from 2010 to 2018 with counts of adults with HFrEF. Our primary outcome measures were the number of LVAD and HT procedures per 1000 adults with HFrEF. The main exposures were sex, race, ethnicity, and age. We used Poisson regression models to estimate procedure rates adjusted for differences in age, sex, race, and ethnicity. In 2018, the estimated population of adults aged 35 to 84 years with HFrEF was 69 736, of whom 44% were women. Among men, the LVAD rate was 45.6, and the HT rate was 26.9. Relative to men, LVAD and HT rates were 72% and 62% lower among women (P<0.001). Relative to White men, LVAD and HT rates were 25% and 46% lower (P<0.001) among Black men. Among Hispanic men and women and Black women, LVAD and HT rates were similar (P>0.05) or higher (P<0.01) than among their White counterparts.

CONCLUSIONS

Among adults with HFrEF, the use of LVAD and HT is lower among women and Black men. Health systems and policymakers should identify and ameliorate sources of sex and racial inequities.

Do outcomes for heart transplantation differ based on donor and recipient race?

PURPOSE

There are limited data examining the impact of both donor and recipient race on outcomes following orthotopic heart transplant (OHT). The purpose of this study was to evaluate the relationship between donor and recipient race and OHT outcomes.

METHODS

The United Network for Organ Sharing (UNOS) database was retrospectively reviewed from January 2000 to March 2018 for donor hearts. A comparison was conducted based on donor and recipient race (White, Black, Hispanic, Other/Unknown). Races for which there were limited numbers were excluded from the analysis (Asian, n = 1292; American Indian, n = 132; Pacific Islander, n = 132, Multiple ethnicities, n = 225). The primary endpoint was survival at 30 days, 1 year survival, and post-transplant rejection. Logistic and Cox models were used to quantify survival endpoints.

RESULTS

A total of 41 841 OHT were included. Of the recipients, 29 894 (71%) were White, 8475 (20%) were Black, and 3472 (8%) were Hispanic. Of the donors 27 783 (66%) were White, 6277 (15%) were Black, 6576 (16%) were Hispanic, and 1205 (3%) were Unknown/Other race. In a comparison of recipient demographics, White recipients were older (54.09 ± 12.21 years) compared to Black (49.44 ± 12.83 years) and Hispanic (49.97 ± 13.27 years) recipients. All other differences between groups were not clinically significant. Black recipients were more likely to receive a heart with an "urgent" status (probability .80) compared to White (.73) and Hispanic (.75) recipients (p < .001). Hispanic recipients were more likely to receive a transplant when listed as "non-urgent" (Probability .47) compared to White (.37) and Black (.30) recipients (p < .001). In terms of outcomes, compared to White recipients, Hispanic patients experienced a decreased 30-day survival (OR 1.27; p = .011) and 1-year survival (OR 1.17; p = .016). In comparing Donor/Recipient combinations compared to a White Donor/White Recipient combination, overall survival was decreased in White donor/African American recipient (HR 1.36; p < .001), African American donor/African American recipient (HR 1.41; p < .001) and Hispanic donor/African American recipient (HR 1.30; p < .001) combinations (Table 1).

CONCLUSIONS

African American and Hispanic recipients have decreased survival compared to White recipients after heart transplant. The African American donor does not decrease survival. Racial differences still exist in donor and recipient characteristics and recipient outcomes after OHT. Increasing the donor pool for all races and ethnicities would potentially benefit all recipients. Continued study is warranted in order to minimize these differences among recipients and identify factors that could be contributing to decreased survival, in order to optimize outcomes for African American and Hispanic recipients post-transplant and eliminate disparities.

Improvement in Racial Disparities in Heart Transplantation following the Heart Allocation Policy Change

Objectives. Heart transplantation (HT) is a definitive therapy for refractory heart failure, making it the gold-standard treatment for recipients with end-stage disease. Heart allocation policy (HAP) in the United States was changed on October 18th, 2018. The aim of this study was to assess the effect of the new policy on racial disparities in heart transplantation (HT) outcomes. Methods. The United Network for Organ Sharing (UNOS) registry was used to identify adult recipients undergoing isolated HT between 2010 and 2021. Recipients were stratified into pre-HAP (January 2010 to September 2018) vs. post-HAP (October 2018 to September 2021). Recipient race was classified as White, Black, Hispanic, or other. The primary outcome was post-HT mortality. Cox proportional hazard models were used for risk-adjustment in evaluating the independent effect of race on post-HT mortality. Results. A total of 27,403 recipients underwent HT in 143 centers during study period. The proportion of non-Whites undergoing HT increased in the post-HAP era: (pre-HAP: White 66.0%, Black 21.2%, Hispanic 8.2%, Other 4.6% versus post-HAP: White 62.5%, Black 23.2%, Hispanic 9.5%, Other 4.8%; $p<0.001$ ). In risk-adjusted analysis, Black recipients were at higher risk of post-HT mortality in the pre-HAP era (HR 1.31, 95% CI 1.22–1.41; $p<0.001$ ) but not in the post-HAP era (HR 1.12, 95% CI 0.03–1.34; $p=0.222$ ) compared to White recipients. Other non-White recipients had comparable risk-adjusted post-HT mortality rates compared to White recipients both in the pre-HAP and post-HAP eras. Conclusions. Under the new heart allocation system, a higher percentage of recipients are non-White. In addition, racial disparities in HT outcomes have improved with Black recipients no longer having an increased risk-adjusted mortality following HT.

Racial disparities in post-transplant stroke and mortality following stroke in adult cardiac transplant recipients in the United States

Black heart transplant recipients have a higher mortality rate than white recipients 6-12 months after transplant. Whether there are racial disparities in post-transplant stroke incidence and all-cause mortality following post-transplant stroke among cardiac transplant recipients is unknown. Using a nationwide transplant registry, we assessed the association between race and incident post-transplant stroke using logistic regression and the association between race and mortality among adults who survived a post-transplant stroke using Cox proportional hazards regression. We found no evidence of an association between race and the odds of post-transplant stroke (OR = 1.00, 95% CI: 0.83-1.20). The median survival time of those with a post-transplant stroke in this cohort was 4.1 years (95% CI: 3.0, 5.4). There were 726 deaths among the 1139 patients with post-transplant stroke, including 127 deaths among 203 Black patients and 599 deaths among 936 white patients. Among post-transplant stroke survivors, Black transplant recipients experienced a 23% higher rate of mortality compared to white recipients (HR = 1.23, 95% CI: 1.00-1.52). This disparity is strongest in the period beyond the first 6 months and appears to be mediated by differences in the post-transplant setting of care between Black and white patients. The racial disparity in mortality outcomes was not evident in the past decade. The improved survival of Black patients in the recent decade may reflect overall protocol improvements for heart transplant recipients irrespective of race, such as advancements in surgical techniques and immediate postoperative care as well as increased awareness about reducing racial disparities.

Post-transplant mortality and graft failure after induction immunosuppression among Black heart transplant recipients in the United States

Black heart transplant recipients are more likely to receive induction immunosuppression compared to other races because of higher rates of acute rejection, graft failure, and mortality. However, it is not known whether contemporary induction immunosuppression improves their post-transplant outcomes. To evaluate whether Black patients who were prescribed induction immunosuppression therapy have lower all-cause mortality or graft-failure rates compared to those who were not, we studied Black U.S. adult heart transplant recipients in the Scientific Registry of Transplant Recipients database (2008-2018). We used multivariable Cox proportional hazards regression analysis to compare the hazards of all-cause mortality or graft failure as a composite, for patients who were prescribed induction immunosuppression and those who were not. Among 5160 recipients, 2787 (54.0%) were prescribed induction immunosuppression and 2373 (46.0%) were not. There was no evidence of survival differences according to induction immunosuppression for the composite of all-cause mortality or graft failure (aHR = 1.13, 95% CI 0.96-1.32), mortality (aHR = 1.14, 95% CI 0.97-1.34), graft failure (aHR = 1.05, 95% CI 0.82-1.34) and acute rejection (aHR = 1.00, 95% CI 0.89-1.12). Given the side effects of treatment, future guidelines should reconsider the recommendation for induction immunosuppression among Black patients.

Disparities in Social Determinants of Health Among Patients Receiving Liver Transplant: Analysis of the National Inpatient Sample From 2016 to 2019

Background

Liver transplantation is the life-saving standard of care for those with end-stage liver disease. Unfortunately, many patients on the liver transplant list die waiting. Several studies have demonstrated significant differences based on disparities in race, gender, and multiple socioeconomic factors. We sought to evaluate recent disparities among patients receiving liver transplants using the latest available data from the National Inpatient Sample (NIS), the largest publicly available inpatient care database in the United States.

Methods

We performed an analysis of discharge data from the NIS between 2016 and 2019. We identified adult patients with chronic liver disease who underwent a liver transplant using the International Classification of Diseases, 10th revision (ICD-10) codes. Multivariate logistic regression was used to adjust for differences in race, gender, socioeconomic status, and comorbidities among those who received a liver transplant.

Results

A total of 24,595 liver transplants were performed over the study period. Female gender was independently associated with decreased transplant rates (adjusted odds ratio (AOR) 0.83, 95% confidence interval (CI), 0.78-0.89, P < 0.001). Compared to White patients, Black patients had decreased transplant rates (AOR 0.86, 95% CI, 0.75-0.99, P = 0.034), as did Native Americans (AOR 0.64; 95% CI, 0.42-0.97, P = 0.035). Hispanics and Asian Americans had increased rates of liver transplantation (AOR 1.16, 95% CI 1.02-1.32, P = 0.022, and 1.36, 95% CI 1.11-1.67, P = 0.003; respectively). The increase in income quartile was associated with an incremental increase in transplant rates. Additionally, patients with private insurance had much higher transplant rates compared to those with Medicare (AOR 2.50, 95% CI 2.31-2.70, P < 0.001) while patients without insurance had the lowest rates of transplantation (AOR 0.18, 95% CI 0.12-0.28, P < 0.001).

Conclusions

Our analysis demonstrates that race, gender, and other social determinants of health have significant impacts on the likelihood of receiving a liver transplant. Our study, on a national level, confirms previously described disparities in receiving liver transplantation. Patient-level studies are needed to better understand how these variables translate into differing liver transplantation rates.