Systemic Kidney Transplant Inequities for Black Individuals: Examining the Contribution of Racialized Kidney Function Estimating Equations

Towards equitable AI in oncology

Artificial intelligence (AI) stands at the threshold of revolutionizing clinical oncology, with considerable potential to improve early cancer detection and risk assessment, and to enable more accurate personalized treatment recommendations. However, a notable imbalance exists in the distribution of the benefits of AI, which disproportionately favour those living in specific geographical locations and in specific populations. In this Perspective, we discuss the need to foster the development of equitable AI tools that are both accurate in and accessible to a diverse range of patient populations, including those in low-income to middle-income countries. We also discuss some of the challenges and potential solutions in attaining equitable AI, including addressing the historically limited representation of diverse populations in existing clinical datasets and the use of inadequate clinical validation methods. Additionally, we focus on extant sources of inequity including the type of model approach (such as deep learning, and feature engineering-based methods), the implications of dataset curation strategies, the need for rigorous validation across a variety of populations and settings, and the risk of introducing contextual bias that comes with developing tools predominantly in high-income countries.

Navigating Living Kidney Donation and Transplantation Among South Asian Canadians: The ACTION Project

RATIONALE & OBJECTIVE

South Asian (SA) Canadians with kidney failure have a 50%-77% lower likelihood of kidney transplant and are less likely to identify potential living donors (LDs). This study aimed to identify health system-, patient-, and community-level barriers and facilitators for accessing LD kidney transplantation in the SA community to inform the development of health system- and community-level interventions to address barriers.

STUDY DESIGN

Qualitative study.

SETTING & PARTICIPANTS

20 SA recipients of an LD or deceased-donor kidney transplant, 10 SA LDs, and 41 general SA community members.

ANALYTICAL APPROACH

In-depth multilingual interviews were conducted with recipients and LDs. Gender-, language-, and age-stratified focus groups were conducted with general SA community members. Summative content analysis was used to analyze the data.

RESULTS

Hesitancy in approaching potential donors, fear about the health of potential LDs, information gaps, language barriers, and challenges evaluating out-of-country donors were highlighted as significant barriers by recipients, and financial concerns and information gaps were identified by donors. Cultural barriers in the SA community were highlighted by donors, recipients, and community members as critical factors when considering donation and transplant; women and elderly SA Canadians highlighted nuanced challenges. Participants reported generally a favorable perception of their health care teams, citing SA representation in the teams as important to providing culturally and linguistically sensitive care.

LIMITATIONS

Limited geographic, race, and cultural representation and reliance on virtual data collection.

CONCLUSIONS

This study highlights several culturally relevant barriers to donation and transplant that are potentially modifiable through patient-, health system-, and community-focused engagement and education.

Racialized and Immigrant Status and the Pursuit of Living Donor Kidney Transplant - a Canadian Cohort Study

Introduction

Both immigrant and racialized status may be associated with the pursuit of living donor kidney transplant (LDKT).

Methods

This study was a secondary analysis of a convenience cross-sectional sample of patients with kidney failure in Toronto, obtained from our "Comprehensive Psychosocial Research Data System" research database. The exposures included racialized, immigrant, and combined immigrant and racialized status (White nonimmigrant, racialized nonimmigrant, White immigrant and racialized immigrant). Outcomes include the following: (i) having spoken about LDKT with others, (ii) having a potential living donor (LD) identified, (iii) having allowed others to share the need for LDKT, (iv) having directly asked a potential donor to be tested, and (v) accept a hypothetical LDKT offer. We assessed the association between exposure and outcomes using univariable, and multivariable binary or multinominal logistic regression (reference: White or White nonimmigrant participants).

Results

Of the 498 participants, 281 (56%) were immigrants; 142 (28%) were African, Caribbean, and Black (ACB); 123 (25%) were Asian; and 233 (47%) were White. Compared to White nonimmigrants, racialized immigrants (relative risk ratio [RRR]: 2.98; 95% confidence interval [CI]: 1.76-5.03) and racialized nonimmigrants (RRR: 2.84; 95% CI: 1.22-6.65) were more likely not to have spoken about LDKT with others (vs. having spoken or planning to do so). Both racialized immigrant (odds ratio [OR]: 4.07; 95% CI: 2.50-6.34), racialized nonimmigrants (OR: 2.68; 95% CI: 1.31-5.51) and White immigrants (OR: 2.68; 95% CI: 1.43-5.05) were more likely not to have a potential LD identified.

Conclusion

Both racialized and immigrant status are associated with less readiness to pursue LDKT. Supporting patients to communicate their need for LDKT may improve equitable access to LDKT.

Reviewing Racial Disparities in Living Donor Kidney Transplantation: a Socioecological Approach

Despite kidney transplantation having superior outcomes to dialytic therapies, disparities continue to exist among rates of kidney transplantation between Black and non-Hispanic White patients, which cannot be explained by differences in individual characteristics. To better evaluate the persistent Black/White disparities in living kidney transplantation, we review the extant literature and include the critical factors and recent development in living kidney transplantation in the socioecological approach. We also emphasize the potential vertical and hierarchical associations among factors in the socioecological model. Specifically, this review explores the possibility that the relatively low living kidney transplantation among Blacks may be a consequence of individual, interpersonal, and structural inequalities in various social and cultural dimensions. At the individual level, the Black/White differences in socioeconomic conditions and transplant knowledge may account for the low transplantation rates among Blacks. Interpersonally, the relatively weak social support and poor communication between Black patients and their providers may contribute to disparities. At the structural level, the race-based glomerular filtration rate (GFR) calculation that is widely used to screen Black donors is a barrier to receiving living kidney transplantation. This factor is directly related to structural racism in the health care system but its potential impact on living donor transplantation is underexplored. Finally, this literature review emphasizes the current perspective that a race-free GFR should be considered and a multidisciplinary and interprofessional perspective is necessary to devise strategies and interventions to reduce the Black/White disparities in living donor kidney transplantation in the U.S.

Clearing the air: a review of the effects of air pollution on dialysis outcomes

PURPOSE OF REVIEW

An evolving body of literature indicates exposure to air pollutants is associated with adverse health outcomes in dialysis patients. As the prevalence of kidney disease increases, understanding the role of environmental agents on the health of dialysis patients is critical to reducing global morbidity and mortality.

RECENT FINDINGS

We identified 16 publications that investigated associations between pollutants including particulate matter (PM 2.5 and PM 10 ), carbon monoxide (CO), nitrogen dioxide (NO 2 ), sulfur dioxide (SO 2 ), and ozone (O 3 ) and health outcomes among dialysis patients. Eight studies examined the effects of particulate matter (PM) and four studies examined the effects CO exposure on dialysis patients. Exposure to PM was consistently associated with outcomes including all-cause mortality and a smaller body of literature suggested relationships with subclinical outcomes. Exposure to CO was associated with all-cause mortality, generalized inflammation, and uremic pruritus. An additional four studies examined multiple pollutant exposures including NO 2 , SO 2 , and O 3 and reported associations with all-cause mortality in dialysis patients.

SUMMARY

This review emphasized the nascent literature that demonstrates consistent relationships between air pollutant exposure and adverse outcomes among dialysis patients. Further research is needed to assess the impact of air pollutants, including how co-exposures will impact dialysis patient health.

Impact of OPTN policy 3.7D providing waiting time modification for candidates affected by race-inclusive eGFR calculations: Early results from a single center

INTRODUCTION

OPTN Policy 3.7D, implemented January 5, 2023, mandates that all kidney transplant programs modify waiting time for candidates affected by race-inclusive eGFR calculations. We report the early impact of this policy change.

METHODS

Our transplant program reviewed all listed transplant candidates and identified patients potentially eligible for waiting time modification. Eligible candidates received waiting time modification after submission of supporting evidence to the OPTN. We reviewed the impact on waiting time and transplant activity through October 1, 2023.

RESULTS

Forty-six adult patients on our center's active waiting list self-identified as Black/African American. 25 (54.3%) candidates qualified for waiting time modification. A median 451 (321, 1543.5) additional days of waiting time was added for qualifying patients. Of the 25 patients who qualified for waiting time modification, 11 patients received a deceased donor kidney in the early period following waiting time modification, including 5 patients transplanted within 1 month after modification.

CONCLUSIONS

Policy 3.7D is one of few national mandates to address specifically structural racism within transplantation. Implementation has yielded near immediate effects with greater than 40% of time-adjusted patients at our center receiving a deceased donor kidney transplant in the initial months after policy enactment. Early assessment demonstrates great potential impact for this policy.

Pressing ethical issues relating to clinical pig organ transplantation studies

Clinical pig heart transplant experiments have been undertaken, and further clinical experiments and/or clinical trials of gene-edited pig organ xenotransplantation are anticipated. The ethical issues relating to xenotransplantation have been discussed for decades but with little resolution. Consideration of certain ethical issues is more urgent than others, and the need to attain consensus is important. These issues include: (i) patient selection criteria for expanded access and/or clinical trials; (ii) appropriate protection of the patient from xenozoonoses, that is, infections caused by pig microorganisms transferred with the organ graft, (iii) minimization of the risk of a xenozoonosis to bystanders, and (iv) the need for additional public perception studies. We discuss why it is important and urgent to achieve consensus on these ethical issues prior to carrying out further expanded access experiments or initiating formal clinical trials. The ways forward on each issue are proposed.

Perceptions of Data Set Experts on Important Characteristics of Health Data Sets Ready for Machine Learning: A Qualitative Study

Importance

The lack of data quality frameworks to guide the development of artificial intelligence (AI)-ready data sets limits their usefulness for machine learning (ML) research in health care and hinders the diagnostic excellence of developed clinical AI applications for patient care.

Objective

To discern what constitutes high-quality and useful data sets for health and biomedical ML research purposes according to subject matter experts.

Design, Setting, and Participants

This qualitative study interviewed data set experts, particularly those who are creators and ML researchers. Semistructured interviews were conducted in English and remotely through a secure video conferencing platform between August 23, 2022, and January 5, 2023. A total of 93 experts were invited to participate. Twenty experts were enrolled and interviewed. Using purposive sampling, experts were affiliated with a diverse representation of 16 health data sets/databases across organizational sectors. Content analysis was used to evaluate survey information and thematic analysis was used to analyze interview data.

Main Outcomes and Measures

Data set experts' perceptions on what makes data sets AI ready.

Results

Participants included 20 data set experts (11 [55%] men; mean [SD] age, 42 [11] years), of whom all were health data set creators, and 18 of the 20 were also ML researchers. Themes (3 main and 11 subthemes) were identified and integrated into an AI-readiness framework to show their association within the health data ecosystem. Participants partially determined the AI readiness of data sets using priority appraisal elements of accuracy, completeness, consistency, and fitness. Ethical acquisition and societal impact emerged as appraisal considerations in that participant samples have not been described to date in prior data quality frameworks. Factors that drive creation of high-quality health data sets and mitigate risks associated with data reuse in ML research were also relevant to AI readiness. The state of data availability, data quality standards, documentation, team science, and incentivization were associated with elements of AI readiness and the overall perception of data set usefulness.

Conclusions and Relevance

In this qualitative study of data set experts, participants contributed to the development of a grounded framework for AI data set quality. Data set AI readiness required the concerted appraisal of many elements and the balancing of transparency and ethical reflection against pragmatic constraints. The movement toward more reliable, relevant, and ethical AI and ML applications for patient care will inevitably require strategic updates to data set creation practices.

Retaining Race in Chronic Kidney Disease Diagnosis and Treatment

The best overall measure of kidney function is glomerular filtration rate (GFR) as commonly estimated from serum creatinine concentrations (eGFRcr) using formulas that correct for the higher average creatinine concentrations in Blacks. After two decades of use, these formulas have come under scrutiny for estimating GFR differently in Blacks and non-Blacks. Discussions of whether to include race (Black vs. non-Black) in the calculation of eGFRcr fail to acknowledge that the original race-based eGFRcr provided the same CKD treatment recommendations for Blacks and non-Blacks based on directly (exogenously) measured GFR. Nevertheless, the National Kidney Foundation and the American Society of Nephrology Task Force on Reassessing the Inclusion of Race in Diagnosing Kidney Disease removed race in CKD treatment guidelines and pushed for the immediate adoption of a race-free eGFRcr formula by physicians and clinical laboratories. This formula is projected to negate CKD in 5.51 million White and other non-Black adults and reclassify CKD to less severe stages in another 4.59 million non-Blacks, in order to expand treatment eligibility to 434,000 Blacks not previously diagnosed and to 584,000 Blacks previously diagnosed with less severe CKD. This review examines: 1) the validity of the arguments for removing the original race correction, and 2) the performance of the proposed replacement formula. Excluding race in the derivation of eGFRcr changed the statistical bias from +3.7 to -3.6 ml/min/1.73m2 in Blacks and from +0.5 to +3.9 in non-Blacks, i.e., promoting CKD diagnosis in Blacks at the cost of restricting diagnosis in non-Blacks. By doing so, the revised eGFRcr greatly exaggerates the purported racial disparity in CKD burden. Claims that the revised formulas identify heretofore undiagnosed CKD in Blacks are not supported when studies that used kidney failure replacement therapy and mortality are interpreted as proxies for baseline CKD. Alternatively, a race-stratified eGFRcr (i.e., separate equations for Blacks and non-Blacks) would provide the least biased eGFRcr for both Blacks and non-Blacks and the best medical treatment for all patients.

Impact of the New Glomerular Filtration Rate Formulas on Kidney Function Assessment in Living Kidney Donors and Candidates

New estimated glomerular filtration rate (GFR) equations that do not include a race coefficient have been created to better estimate kidney function, reduce inequities in kidney disease care, and improve the historically limited access to transplantation in African Americans. The impact of these new equations on estimated GFR (eGFR) in living donors pre- and postdonation is not known.

Methods

To address this, we conducted a single-center retrospective cohort study of 150 kidney donors and donor candidates. We calculated pre- and postdonation eGFR using the old and new equations and compared them with measured GFR by 2.8 mCi Tc-99m diethylene triamine penta-acetic acid clearance (mGFR_DTPA) and 24-h creatinine clearance (mGFR_CrCl). We evaluated the impact of the new equations on donation eligibility and postdonation eGFR.

Results

We found that using the new eGFR equations resulted in higher predonation eGFR compared with the old equations but remained significantly lower than mGFR_DTPA and mGFR_CrCl. We also found that using the new eGFR equations would not exclude any potential donors based on our center's GFR criteria for donation. At 6 mo postdonation, the new equations resulted in higher eGFR values compared with the old equations.

Conclusions

The new eGFR equations continue to underestimate GFR in healthy donor candidates but would not exclude any potential donors from donation and resulted in higher eGFR predonation and postdonation in a predominantly White population. eGFR equations designed specifically for potential kidney donors are still needed for better kidney function assessment.

The Effects of Race on Acute Kidney Injury

Racial disparities in incidence and outcomes of acute kidney injury (AKI) are pervasive and are driven in part by social inequities and other factors. It is well-documented that Black patients face higher risk of AKI and seemingly have a survival advantage compared to White counterparts. Various explanations have been advanced and suggested to account for this, including differences in susceptibility to kidney injury, severity of illness, and socioeconomic factors. In this review, we try to understand and further explore the link between race and AKI using the incidence, diagnosis, and management of AKI to illustrate how race is directly related to AKI outcomes, with a focus on Black and White individuals with AKI. In particular, we explore the effect of race-adjusted estimated glomerular filtration rate (eGFR) equation on AKI prediction and discuss racial disparities in the management of AKI and how this might contribute to racial differences in AKI-related mortality among Blacks with AKI. We also identify some opportunities for future research and advocacy.

Impact of Race-Adjusted Glomerular Filtration Rate Estimation on Eligibility for Simultaneous Liver-Kidney Transplantation

Estimated glomerular filtration rate (eGFR) is adjusted for Black race in commonly used formulas. This has potential implications for access to simultaneous liver-kidney transplantation (SLKT) as qualifying criteria rely on eGFR. We performed a retrospective study of United Network for Organ Sharing national transplant registry data between February 28, 2002, and March 31, 2019, to evaluate the proportion of Black patients who would be reclassified as meeting SLKT criteria (as defined per current policies) if race adjustment were removed from 2 prominent eGFR equations (Modification of Diet in Renal Disease-4 [MDRD-4] and Chronic Kidney Disease Epidemiology Collaboration [CKD-EPI]). Of the 7937 Black patients listed for transplant during the study period, we found that 3.6% would have been reclassified as qualifying for chronic kidney disease (CKD)-related SLKT with removal of race adjustment for MDRD-4, and 3.0% would have been reclassified with CKD-EPI; this represented 23.7% and 18.7% increases in SLKT candidacy, respectively. Reclassification impacted women more than men (eg, 4.5% versus 3.0% by MDRD-4; P < 0.05). In an exploratory analysis, patients meeting SLKT criteria by race-unadjusted eGFR equations were significantly more likely to receive liver transplantation alone (LTA) compared with SLKT. Approximately 2.0% of reclassified patients required kidney transplantation within 1 year of LTA versus 0.3% of nonreclassified patients. In conclusion, race adjustment in eGFR equations may impact SLKT candidacy for 3.0% to 4.0% of Black patients listed for LTA overall. Approximately 2.0% of patients reclassified as meeting SLKT criteria require short-term post-LTA kidney transplantation. These data argue for developing novel algorithms for glomerular filtration rate estimation free of race to promote equity.

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.

OUP accepted manuscript

Objective

Health care providers increasingly rely upon predictive algorithms when making important treatment decisions, however, evidence indicates that these tools can lead to inequitable outcomes across racial and socio-economic groups. In this study, we introduce a bias evaluation checklist that allows model developers and health care providers a means to systematically appraise a model’s potential to introduce bias.

Materials and Methods

Our methods include developing a bias evaluation checklist, a scoping literature review to identify 30-day hospital readmission prediction models, and assessing the selected models using the checklist.

Results

We selected 4 models for evaluation: LACE, HOSPITAL, Johns Hopkins ACG, and HATRIX. Our assessment identified critical ways in which these algorithms can perpetuate health care inequalities. We found that LACE and HOSPITAL have the greatest potential for introducing bias, Johns Hopkins ACG has the most areas of uncertainty, and HATRIX has the fewest causes for concern.

Discussion

Our approach gives model developers and health care providers a practical and systematic method for evaluating bias in predictive models. Traditional bias identification methods do not elucidate sources of bias and are thus insufficient for mitigation efforts. With our checklist, bias can be addressed and eliminated before a model is fully developed or deployed.

Conclusion

The potential for algorithms to perpetuate biased outcomes is not isolated to readmission prediction models; rather, we believe our results have implications for predictive models across health care. We offer a systematic method for evaluating potential bias with sufficient flexibility to be utilized across models and applications.

A Cascade of Structural Barriers Contributing to Racial Kidney Transplant Inequities

Stark racial disparities in access to and receipt of kidney transplantation, especially living donor and pre-emptive transplantation, have persisted despite decades of investigation and intervention. The causes of these disparities are complex, are inter-related, and result from a cascade of structural barriers to transplantation which disproportionately impact minoritized individuals and communities. Structural barriers contributing to racial transplant inequities have been acknowledged but are often not fully explored with regard to transplant equity. We describe longstanding racial disparities in transplantation, and we discuss contributing structural barriers which occur along the transplant pathway including pretransplant health care, evaluation, referral processes, and the evaluation of transplant candidates. We also consider the role of multilevel socio-contextual influences on these processes. We believe focused efforts which apply an equity lens to key transplant processes and systems are required to achieve greater structural competency and, ultimately, racial transplant equity.

Elucidating measures of systemic racism to mitigate racial disparities in kidney transplantation

PURPOSE OF REVIEW

Given recent national attention to the role of racism in perpetuating racial inequities in society and health, this review provides a timely and relevant summary of key measures of systemic racism in kidney transplantation. More specifically, the review identifies current and promising interventions, whereas highlighting the need for more sustainable and impactful interventions.

RECENT FINDINGS

Racial disparities persist in kidney transplantation. Black and Hispanic individuals are less likely to receive a kidney transplant than non-Hispanic Whites despite disproportionately higher rates of kidney failure. Studies demonstrate that socioeconomic factors do not fully explain existing racial disparities in transplantation. Systemic racism at all levels, individual, interpersonal, institutional, and structural, is at the core of racial disparities, and current interventions are insufficient in mitigating their effects. Thus, targeted and sustainable interventions must be implemented to mitigate systemic racism in kidney transplantation.

SUMMARY

Systemic racism in all its forms continues to influence disparities at all stages of kidney transplantation. This paper highlights recent findings that shed light on how racism contributes to racial disparities in kidney transplantation. Using these findings to identify targets and strategies for mitigation, relevant interventions and policies that show promise are detailed.