APOL1, Black Race, and Kidney Disease: Turning Attention to Structural Racism

Monogenic and polygenic concepts in chronic kidney disease (CKD)

Kidney function is strongly influenced by genetic factors with both monogenic and polygenic factors contributing to kidney function. Monogenic disorders with primarily autosomal dominant inheritance patterns account for 10% of adult and 50% of paediatric kidney diseases. However, kidney function is also a complex trait with polygenic architecture, where genetic factors interact with environment and lifestyle factors. Family studies suggest that kidney function has significant heritability at 35-69%, capturing complexities of the genome with shared environmental factors. Genome-wide association studies estimate the single nucleotide polymorphism-based heritability of kidney function between 7.1 and 20.3%. These heritability estimates, measuring the extent to which genetic variation contributes to CKD risk, indicate a strong genetic contribution. Polygenic Risk Scores have recently been developed for chronic kidney disease and kidney function, and validated in large populations. Polygenic Risk Scores show correlation with kidney function but lack the specificity to predict individual-level changes in kidney function. Certain kidney diseases, such as membranous nephropathy and IgA nephropathy that have significant genetic components, may benefit most from polygenic risk scores for improved risk stratification. Genetic studies of kidney function also provide a potential avenue for the development of more targeted therapies and interventions. Understanding the development and validation of genomic scores is required to guide their implementation and identify the most appropriate potential implications in clinical practice. In this review, we provide an overview of the heritability of kidney function traits in population studies, explore both monogenic and polygenic concepts in kidney disease, with a focus on recently developed polygenic risk scores in kidney function and chronic kidney disease, and review specific diseases which are most amenable to incorporation of genomic scores.

Repetitive administration of rituximab can achieve and maintain clinical remission in patients with MCD or FSGS

Minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) are glomerulopathies associated with nephrotic syndrome. Primary forms of these diseases are treated with various regimes of immunosuppression. Frequently relapsing or glucocorticoid-dependent courses remain challenging. Here, a B-cell-depleting strategy with rituximab represents a salvage option although data are sparse in the adult population. In particular, there is limited evidence on the efficacy of restoring remission after initial successful treatment with rituximab and whether patients benefit from an individualized, relapse-based approach. We identified 13 patients who received multiple therapies with rituximab from the FOrMe-registry (NCT03949972), a nationwide registry for MCD and FSGS in Germany, or from the University Hospital of Cologne. Disease status, changes in serum creatinine, proteinuria, and time to relapse were evaluated. Relapse-free survival was compared to the patients' previous therapy regimens. Through all treatment cycles, an improvement of disease activity was shown leading to a complete remission in 72% and partial remission in 26% after 3 ([Formula: see text]0.001) and 6 months ([Formula: see text]0.001). Relapse-free survival increased from 4.5 months (95%-CI 3-10 months) to 21 months (95%-CI 16-32 months) ([Formula: see text]0.001) compared to previous immunosuppression regimens with no loss in estimated glomerular filtration over time (p = 0.53). Compared to continuous B-cell depletion, an individualized relapse-based approach led to a reduced rituximab exposure and significant cost savings. Relapse-based administration of rituximab in patients with MCD/FSGS with an initial good clinical response did not result in a decreased efficacy at a median follow-up duration of 110 months. Thus, reinduction therapies may provide an alternative to continuous B-cell-depletion and reduce the long-term side effects of continuous immunosuppression.

The Use of Race in Risk Assessment Tools Contributes to Systemic Racism

Many patients suffer from hip or knee osteoarthritis and elect to pursue total joint arthroplasty (TJA). Though perioperative risk is an inherent component of surgery, calculators that assess the risk of complications following TJA can help both surgeons and patients make informed decisions about the risk of surgery and aid in shared decision-making discussions. The inclusion of race in a risk calculator for readmission after TJA is flawed and unacceptable because a patient's race does not increase their risk of a complication after total joint replacement.

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.

Race-based medicine in the point-of-care clinical resource UpToDate: A systematic content analysis

BACKGROUND

Race-based practices in medical education and clinical care may exacerbate health inequities. Misguided use of race in popular point-of-care clinical decision-making tools like UpToDate® may promote harmful practices of race-based medicine. This article investigates the nature of mentions of Black/African American race in UpToDate®.

METHODS

We conducted a systematic content analysis of UpToDate® articles mentioning Black or African American race to assess for biological interpretations of racial categories. Following a simple text search for the terms "Black" and "African American" in UpToDate® on January 24 and March 19, 2020, respectively, removal of duplicates yielded an analytical sample of 208 documents. We adopted a deductive coding approach and systematically applied 16 a priori codes to all documents, refining the codebook to achieve a final inter-rater reliability of 0.91. We then developed these codes into two themes: (1) biologization of race and (2) racialized research and practice.

FINDINGS

Biologization of race occurred nearly universally across all documents (93.3%), with discussions of inherent physiological differences between racial groups and presentation of epidemiologic disparities without context emerging most frequently. Sixty-eight documents (32.7%) included codes related to racialized biomedical research and clinical practice, including references to racialized patterns of behavior and cultural practices, insufficient data on Black populations, research limiting study to a specific racial group, and race-based clinical practices guidelines.

INTERPRETATION

Our findings suggest that UpToDate® articles often inappropriately link Black race to genetics or clinical phenotype-without considering socio-structural variables or the health effects of structural racism-thus perpetuating a false narrative that race is inherently biological. UpToDate® articles may also promote unequal treatment by recommending race-based clinical practices. Such racial essentialism risks exacerbating racialized health inequities.

FUNDING

The study is supported by the Health Policy Research Scholars Program, Robert Wood Johnson Foundation, Medical Scientist Training Program, National Institutes of Health, the National Science Foundation, the JPB Foundation, the Minnesota Population, the Eunice Kennedy Shriver National Institute for Child Health and Human Development (NICHD), and the Center for Antiracism Research for Health Equity at the University of Minnesota.

Genomic supremacy: the harm of conflating genetic ancestry and race

BACKGROUND

Recent studies have reignited the tinderbox of debate surrounding the use of race and ancestry in medicine. These controversial studies have argued for a strong correlation between genetic ancestry and race, justifying continued use of genetic ancestry measures in studies of disease. These studies contend that increased use of continental ancestry estimates can inform clinical risk assessments and management. Further, recent studies of racial corrections used in clinical algorithms, such as those used to estimate 'normal' lung function, also advocate for use of genetic ancestry in place of race for refining risk algorithms.

MAIN BODY

These positions are misleading, harmful, and reflect superficial interpretations of population genetics. In this Perspective, we argue that continental genetic ancestry, often proxied by race, serves as a poor indicator of disease risk, and reinforces racialized inequities.

CONCLUSION

Instead, we endorse that racial disparities in disease should be investigated by rigorous measures of structural racism alongside careful measures of genetic factors in relevant disease pathways, rather than relying on genetic ancestry or race as a crude proxy for disease-causing alleles.

A biosocial return to race? A cautionary view for the postgenomic era

Recent studies demonstrating epigenetic and developmental sensitivity to early environments, as exemplified by fields like the Developmental Origins of Health and Disease (DOHaD) and environmental epigenetics, are bringing new data and models to bear on debates about race, genetics, and society. Here, we first survey the historical prominence of models of environmental determinism in early formulations of racial thinking to illustrate how notions of direct environmental effects on bodies have been used to naturalize racial hierarchy and inequalities in the past. Next, we conduct a scoping review of postgenomic work in environmental epigenetics and DOHaD that looks at the role of race/ethnicity in human health (2000–2021). Although there is substantial heterogeneity in how race is conceptualized and interpreted across studies, we observe practices that may unwittingly encourage typological thinking, including: using DNA methylation as a novel marker of racial classification; neglect of variation and reversibility within supposedly homogenous racial groups; and a tendency to label and reify whole groups as pathologized or impaired. Even in the very different politico‐economic and epistemic context of contemporary postgenomic science, these trends echo deeply held beliefs in Western thinking which claimed that different environments shape different bodies and then used this logic to argue for essential differences between Europeans and non‐Europeans. We conclude with a series of suggestions on interpreting and reporting findings in these fields that we feel will help researchers harness this work to benefit disadvantaged groups while avoiding the inadvertent dissemination of new and old forms of stigma or prejudice.

Rates of Cardiovascular Disease and CKD Progression in Young Adults with CKD across Racial and Ethnic Groups

Background

Significant racial and ethnic disparities in cardiovascular (CV) and kidney function outcomes in older adults with chronic kidney disease (CKD) have been reported. However, little is known about the extent to which these disparities exist in patients with CKD during the foundational period of young adulthood. The objective of this study was to determine risk factors and rates of CV disease and CKD progression in young adults with CKD across racial and ethnic groups.

Methods

We studied all participants aged 21-40 years of age enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study (n=317). Baseline CV risk factors were described across racial and ethnic groups.

Results

Outcomes included CV events or death (first incidence of heart failure, myocardial infarction, and stroke or death) and CKD progression (>50% decline in eGFR from baseline or end stage kidney disease [ESKD]). Incidence rate ratios (IRRs) were compared as a secondary analysis for participants identifying as Black or Hispanic with those identifying as White or another race and ethnicity. Adjusted models included age, sex, and per APOL1 high-risk allele. CV risk factors were higher in Black and Hispanic participants, including mean SBP, BMI, median UACr, and LDL. Black and Hispanic participants had higher incidence rates of HF (17.5 versus 5.1/1000 person-years), all-cause mortality (15.2 versus 7.1/1000 person-years), and CKD progression (125 versus 59/1000 person-years).

Conclusions

In conclusion, we found a higher prevalence of CV risk factors, some modifiable, in young adults with CKD who identify as Black or Hispanic. Future strategies to ameliorate the racial and ethnic inequality in health outcomes earlier in life for patients with CKD should be prioritized.

Health inequities and the inappropriate use of race in nephrology

Chronic kidney disease is an important clinical condition beset with racial and ethnic disparities that are associated with social inequities. Many medical schools and health centres across the USA have raised concerns about the use of race - a socio-political construct that mediates the effect of structural racism - as a fixed, measurable biological variable in the assessment of kidney disease. We discuss the role of race and racism in medicine and outline many of the concerns that have been raised by the medical and social justice communities regarding the use of race in estimated glomerular filtration rate equations, including its relationship with structural racism and racial inequities. Although race can be used to identify populations who experience racism and subsequent differential treatment, ignoring the biological and social heterogeneity within any racial group and inferring innate individual-level attributes is methodologically flawed. Therefore, although more accurate measures for estimating kidney function are under investigation, we support the use of biomarkers for determining estimated glomerular filtration rate without adjustments for race. Clinicians have a duty to recognize and elucidate the nuances of racism and its effects on health and disease. Otherwise, we risk perpetuating historical racist concepts in medicine that exacerbate health inequities and impact marginalized patient populations.

Use of Race in Kidney Research and Medicine: Concepts, Principles, and Practice

Black Americans and other racially and ethnically minoritized individuals are disproportionately burdened by higher morbidity and mortality from kidney disease when compared with their White peers. Yet, kidney researchers and clinicians have struggled to fully explain or rectify causes of these inequalities. Many studies have sought to identify hypothesized genetic and/or ancestral origins of biologic or behavioral deficits as singular explanations for racial and ethnic inequalities in kidney health. However, these approaches reinforce essentialist beliefs that racial groups are inherently biologically and behaviorally different. These approaches also often conflate the complex interactions of individual-level biologic differences with aggregated population-level disparities that are due to structural racism (i.e., sociopolitical policies and practices that created and perpetuate harmful health outcomes through inequities of opportunities and resources). We review foundational misconceptions about race, racism, genetics, and ancestry that shape research and clinical practice with a focus on kidney disease and related health outcomes. We also provide recommendations on how to embed key equity-enhancing concepts, terms, and principles into research, clinical practice, and medical publishing standards.