Opinions of African American adults about the use of apolipoprotein L1 (ApoL1) genetic testing in living kidney donation and transplantation

Evaluating ApoL1 Genetic Testing Policy Options for Transplant Centers: A Delphi Consensus Panel Project with Stakeholders

BACKGROUND

Apolipoprotein L1 (ApoL1) variants G1 and G2 are associated with a higher risk of kidney disease. ApoL1 risk variants are predominantly seen in individuals with sub-Saharan African ancestry. In most transplant centers, potential organ donors are being selectively genetically tested for ApoL1 risk variants. Transplant programs have highly variable ApoL1 testing practices and need guidance on essential ApoL1 clinical policy questions.

METHODS

We conducted a Delphi consensus panel focused on ApoL1 clinical policy questions, including who gets tested, who decides whether testing occurs, how test results are shared, who receives test results, and how test results are used. A total of 27 panelists across seven stakeholder groups participated: living kidney donors ( n =4), deceased donor family members ( n =3), recipients of a deceased donor kidney ( n =4), recipients of a living donor kidney ( n =4), nephrologists ( n =4), transplant surgeons ( n =4), and genetic counselors ( n =4). Nineteen panelists (70%) identified as Black. The Delphi panel process involved two rounds of educational webinars and three rounds of surveys administered to panelists, who were asked to indicate whether they support, could live with, or oppose each policy option.

RESULTS

The panel reached consensus on one or more acceptable policy options for each clinical policy question; panelists supported 18 policy options and opposed 15. Key elements of consensus include the following: ask potential donors about African ancestry rather than race; make testing decisions only after discussion with donors; encourage disclosure of test results to blood relatives and organ recipients but do not require it; use test results to inform decision making, but never for unilateral decisions by transplant programs.

CONCLUSIONS

The panel generally supported policy options involving discussion and shared decision making among patients, donors, and family stakeholders. There was general opposition to unilateral decision making and prohibiting donation altogether.

Racial Equity in Living Donor Kidney Transplant Centers, 2008-2018

Importance

It is unclear whether center-level factors are associated with racial equity in living donor kidney transplant (LDKT).

Objective

To evaluate center-level factors and racial equity in LDKT during an 11-year time period.

Design, Setting, and Participants

A retrospective cohort longitudinal study was completed in February 2023, of US transplant centers with at least 12 annual LDKTs from January 1, 2008, to December 31, 2018, identified in the Health Resources Services Administration database and linked to the US Renal Data System and the Scientific Registry of Transplant Recipients.

Main Outcomes and Measures

Observed and model-based estimated Black-White mean LDKT rate ratios (RRs), where an RR of 1 indicates racial equity and values less than 1 indicate a lower rate of LDKT of Black patients compared with White patients. Estimated yearly best-case center-specific LDKT RRs between Black and White individuals, where modifiable center characteristics were set to values that would facilitate access to LDKT.

Results

The final cohorts of patients included 394 625 waitlisted adults, of whom 33.1% were Black and 66.9% were White, and 57 222 adult LDKT recipients, of whom 14.1% were Black and 85.9% were White. Among 89 transplant centers, estimated yearly center-level RRs between Black and White individuals accounting for center and population characteristics ranged from 0.0557 in 2008 to 0.771 in 2018. The yearly median RRs ranged from 0.216 in 2016 to 0.285 in 2010. Model-based estimations for the hypothetical best-case scenario resulted in little change in the minimum RR (from 0.0557 to 0.0549), but a greater positive shift in the maximum RR from 0.771 to 0.895. Relative to the observed 582 LDKT in Black patients and 3837 in White patients, the 2018 hypothetical model estimated an increase of 423 (a 72.7% increase) LDKTs for Black patients and of 1838 (a 47.9% increase) LDKTs for White patients.

Conclusions and Relevance

In this cohort study of patients with kidney failure, no substantial improvement occurred over time either in the observed or the covariate-adjusted estimated RRs. Under the best-case hypothetical estimations, modifying centers' participation in the paired exchange and voucher programs and increased access to public insurance may contribute to improved racial equity in LDKT. Additional work is needed to identify center-level and program-specific strategies to improve racial equity in access to LDKT.

Attitudes and beliefs regarding race-targeted genetic testing of Black people: A systematic review

Geographical ancestry has been associated with an increased risk of various genetic conditions. Race and ethnicity often have been used as proxies for geographical ancestry. Despite numerous problems associated with the crude reliance on race and ethnicity as proxies for geographical ancestry, some genetic testing in the clinical, research, and employment settings has been and continues to be race- or ethnicity-based. Race-based or race-targeted genetic testing refers to genetic testing offered only or primarily to people of particular racial or ethnic groups because of presumed differences among groups. One current example is APOL1 testing of Black kidney donors. Race-based genetic testing raises numerous ethical and policy questions. Given the ongoing reliance on the Black race in genetic testing, it is important to understand the views of people who identify as Black or are identified as Black (including African American, Afro-Caribbean, and Hispanic Black) regarding race-based genetic testing that targets Black people because of their race. We conducted a systematic review of studies and reports of stakeholder-engaged projects that examined how people who identify as or are identified as Black perceive genetic testing that specifically presumes genetic differences exist among racial groups or uses race as a surrogate for ancestral genetic variation and targets Black people. Our review identified 14 studies that explicitly studied this question and another 13 that implicitly or tacitly studied this matter. We found four main factors that contribute to a positive attitude toward race-targeted genetic testing (facilitators) and eight main factors that are associated with concerns regarding race-targeted genetic testing (barriers). This review fills an important gap. These findings should inform future genetic research and the policies and practices developed in clinical, research, public health, or other settings regarding genetic testing.

Apolipoprotein L1 Opinions of African American Living Kidney Donors, Kidney Transplant Patients, and Nonpatients

INTRODUCTION

The discovery of apolipoprotein L1 (ApoL1) has raised important ethical and clinical questions about genetic testing in the context of living and deceased kidney donation. Largely missing from this discussion are the perspectives of those African Americans (AA) most likely to be impacted by ApoL1 testing.

METHODS

We surveyed 331 AA potential and former living kidney donors (LKDs), kidney transplant candidates and recipients, and nonpatients at three United States transplant programs about their ApoL1 testing attitudes.

RESULTS

Overall, 72% felt that transplant programs should offer ApoL1 testing to AA potential LKDs. If a potential LKD has the high-risk genotype, 79% felt that the LKD should be allowed to make their own donation decision or participate in shared decision-making with transplant doctors. More than half of the potential LKDs (58%) would undergo ApoL1 testing and 81% of former LKDs would take the test now if offered. Most transplant candidates expressed a low likelihood of accepting a kidney from a LKD (79%) or a deceased donor (67%) with the high-risk genotype.

CONCLUSIONS

There is strong support among LKDs and transplant patients for ApoL1 testing when evaluating potential kidney donors of African ancestry. Inclusion of AA stakeholders in developing guidelines and educational programs for ApoL1 testing is critical.

Impact of education on APOL1 testing attitudes among prospective living kidney donors

It is unknown how providing prospective living donors with information about APOL1, including the benefits and drawbacks of testing, influences their desire for testing. In this study, we surveyed 102 participants with self-reported African ancestry and positive family history of kidney disease, recruited from our nephrology waiting room. We assessed views on APOL1 testing before and after presentation of a set of potential benefits and drawbacks of testing and quantified the self-reported level of influence individual benefits and drawbacks had on participants' desire for testing in the proposed context of living donation. The majority of participants (92%) were aware of organ donation and more than half (56%) had considered living donation. And though we found no significant change in response following presentation of the potential benefits and the drawbacks of APOL1 testing by study end significance, across all participants, "becoming aware of the potential risk of kidney disease among your immediate family" was the benefit with the highest mean influence (3.3±1.4), while the drawback with the highest mean influence (2.9±1.5) was "some transplant centers may not allow you to donate to a loved one". This study provides insights into the priorities of prospective living donors and suggests concern for how the information affects family members may strongly influence desires for testing. It also highlights the need for greater community engagement to gain a deeper understanding of the priorities that influence decision making on APOL1 testing.

Stakeholder Perspectives on Returning Nonactionable Apolipoprotein L1 (APOL1) Genetic Results to African American Research Participants

The ethics of returning nonactionable genetic research results to individuals are unclear. Apolipoprotein L1 (APOL1) genetic variants are nonactionable, predominantly found in people of West African ancestry, and contribute to kidney disease disparities. To inform ethical research practice, we interviewed researchers, clinicians, and African American community members (n  =  76) about the potential risks and benefits of returning APOL1 research results. Stakeholders strongly supported returning APOL1 results. Benefits include reciprocity for participants, community education and rebuilding trust in research, and expectation of future actionability. Risks include analytic validity, misunderstanding, psychological burdens, stigma and discrimination, and questionable resource tradeoffs.

Conclusions: APOL1 results should be offered to participants. Responsibly fulfilling this offer requires careful identification of best communication practices, broader education about the topic, and ongoing community engagement.

Apolipoprotein L1 and mechanisms of kidney disease susceptibility

PURPOSE OF REVIEW

Allelic variants in the gene for apolipoprotein L1 (APOL1), found only in individuals of African ancestry, explain a majority of the excess risk of kidney disease in African Americans. However, a clear understanding how the disease-associated APOL1 variants cause kidney injury and the identity of environmental stressors that trigger the injury process have not been determined.

RECENT FINDINGS

Basic mechanistic studies of APOL1 biochemistry and cell biology, bolstered by new antibody reagents and inducible pluripotent stem cell-derived cell systems, have focused on the cytotoxic effect of the risk variants when APOL1 gene expression is induced. Since the APOL1 variants evolved to alter a key protein-protein interaction with the trypanosome serum resistance-associated protein, additional studies have begun to address differences in APOL1 interactions with other proteins expressed in podocytes, including new observations that APOL1 variants may alter podocyte cytoskeleton dynamics.

SUMMARY

A unified mechanism of pathogenesis for the various APOL1 nephropathies still remains unclear and controversial. As ongoing studies have consistently implicated the pathogenic gain-of-function effects of the variant proteins, novel therapeutic development inhibiting the synthesis or function of APOL1 proteins is moving toward clinical trials.