Racial and Ethnic Disparities in Kidney Replacement Therapies Among Adults With Kidney Failure: An Observational Study of Variation by Patient Age

Engineering Equity Into the Promise of Xenotransplantation

Two of the greatest challenges facing kidney transplantation are the lack of donated organs and inequities in who receives a transplant. Xenotransplantation holds promise as a treatment approach that could solve the supply problem. Major advances in gene-editing procedures have enabled several companies to raise genetically engineered pigs for organ donation. These porcine organs lack antigens and have other modifications that should reduce the probability of immunological rejection when transplanted into humans. The US Food and Drug Administration and transplantation leaders are starting to chart a path to test xenotransplants in clinical trials and later integrate them into routine clinical care. Here we provide a framework that industry, regulatory authorities, payers, transplantation professionals, and patient groups can implement to promote equity during every stage in this process. We also call for immediate action. Companies developing xenotransplant technology should assemble patient advocacy boards to bring the concerns of individuals with end-stage kidney disease to the forefront. For trials, xenotransplantation companies should partner with transplant programs with substantial patient populations of racial and ethnic minority groups and that have reciprocal relationships with those communities. Those companies and transplant programs should reach out now to those communities to inform them about xenotransplantation and try to address their concerns. These actions have the potential to make these communities full partners in the promise of xenotransplantation.

Association of Race and Ethnicity With High Longevity Deceased Donor Kidney Transplantation Under the US Kidney Allocation System

RATIONALE & OBJECTIVE

The US Kidney Allocation System (KAS) prioritizes candidates with a≤20% estimated posttransplant survival (EPTS) to receive high-longevity kidneys defined by a≤20% Kidney Donor Profile Index (KDPI). Use of EPTS in the KAS deprioritizes candidates with older age, diabetes, and longer dialysis durations. We assessed whether this use also disadvantages race and ethnicity minority candidates, who are younger but more likely to have diabetes and longer durations of kidney failure requiring dialysis.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

Adult candidates for and recipients of kidney transplantation represented in the Scientific Registry of Transplant Recipients from January 2015 through December 2020.

EXPOSURE

Race and ethnicity.

OUTCOME

Age-adjusted assignment to≤20% EPTS, transplantation of a≤20% KDPI kidney, and posttransplant survival in longevity-matched recipients by race and ethnicity.

ANALYTIC APPROACH

Multivariable logistic regression, Fine-Gray competing risks survival analysis, and Kaplan-Meier and Cox proportional hazards methods.

RESULTS

The cohort included 199,444 candidates (7% Asian, 29% Black, 19% Hispanic or Latino, and 43% White) listed for deceased donor kidney transplantation. Non-White candidates had significantly higher rates of diabetes, longer dialysis duration, and were younger than White candidates. Adjusted for age, Asian, Black, and Hispanic or Latino candidates had significantly lower odds of having a ETPS score of≤20% (odds ratio, 0.86 [95% CI, 0.81-0.91], 0.52 [95% CI, 0.50-0.54], and 0.49 [95% CI, 0.47-0.51]), and were less likely to receive a≤20% KDPI kidney (sub-hazard ratio, 0.70 [0.66-0.75], 0.89 [0.87-0.92], and 0.73 [0.71-0.76]) compared with White candidates. Among recipients with≤20% EPTS scores transplanted with a≤20% KDPI deceased donor kidney, Asian and Hispanic recipients had lower posttransplant mortality (HR, 0.45 [0.27-0.77] and 0.63 [0.47-0.86], respectively) and Black recipients had higher but not statistically significant posttransplant mortality (HR, 1.22 [0.99-1.52]) compared with White recipients.

LIMITATIONS

Provider reported race and ethnicity data and 5-year post transplant follow-up period.

CONCLUSIONS

The US kidney allocation system is less likely to identify race and ethnicity minority candidates as having a≤20% EPTS score, which triggers allocation of high-longevity deceased donor kidneys. These findings should inform the Organ Procurement and Transplant Network about how to remedy the race and ethnicity disparities introduced through KAS's current approach of allocating allografts with longer predicted longevity to recipients with longer estimated posttransplant survival.

PLAIN-LANGUAGE SUMMARY

The US Kidney Allocation System prioritizes giving high-longevity, high-quality kidneys to patients on the waiting list who have a high estimated posttransplant survival (EPTS) score. EPTS is calculated based on the patient's age, whether the patient has diabetes, whether the patient has a history of organ transplantation, and the number of years spent on dialysis. Our analyses show that Asian, Black or African American, and Hispanic or Latino patients were less likely to receive high-longevity kidneys compared with White patients, despite having similar or better posttransplant survival outcomes.

Increased Access, Persistent Disparities: Trends in Disparities in Peritoneal Dialysis (PD) Use, 2009-2019

Peritoneal dialysis (PD) use has increased in the United States since 2009, but how this has affected disparities in PD use is unclear. We used data from the United States Renal Data System to identify a cohort of incident dialysis patients from 2009 to 2019. We used logistic regression models to examine how odds of PD use changed by demographic characteristics. The incident PD population increased by 203% from 2009 to 2019, and the odds of PD use increased in every subgroup. PD use increased more among older people because the odds for those aged 75 years or older increased 15% more per 5-year period compared with individuals aged 18-44 years (odds ratio [OR] 1.68, 95% confidence interval [CI], 1.64 to 1.73 versus OR 1.46, 95% CI, 1.42 to 1.50). The odds of PD use increased 5% more per 5-year period among Hispanic people compared with White people (OR 1.58, 95% CI, 1.53 to 1.63 versus OR 1.51, 95% CI, 1.48 to 1.53). There was no difference in odds of PD initiation among people who were Black, Asian, or of another race. The odds of PD use increased 5% more for people living in urban areas compared with people living in nonurban areas (5-year OR 1.54, 95% CI, 1.52 to 1.56 versus 5-year OR 1.46, 95% CI, 1.42 to 1.50). The odds of PD use increased 7% more for people living in socioeconomically advantaged areas compared with people living in more deprived areas (5-year OR 1.60, 95% CI, 1.56 to 1.63 for neighborhoods with lowest Social Deprivation Index versus 5-year OR 1.50, 95% CI, 1.48 to 1.53 in the most deprived areas). Expansion of PD use led to a reduction in disparities for older people and for Hispanic people. Although PD use increased across all strata of socioeconomic deprivation, the gap in PD use between people living in the least deprived areas and those living in the most deprived areas widened.

Race, Age, and Kidney Transplant Waitlisting Among Patients Receiving Incident Dialysis in the United States

Rationale & Objective

Patients with kidney failure from racial and ethnic minority groups and older patients have reduced access to the transplant waitlist relative to White and younger patients. Although racial disparities in the waitlisting group have declined after the 2014 kidney allocation system change, whether there is intersectionality of race and age in waitlisting access is unknown.

Study Design

Retrospective cohort study.

Setting & Participants

439,455 non-Hispanic White and non-Hispanic Black US adults initiating dialysis between 2015 and 2019 were identified from the United States Renal Data System, and followed through 2020.

Exposures

Patient race and ethnicity (non-Hispanic White and non-Hispanic Black) and age group (18-29, 30-49, 50-64, and 65-80 years).

Outcomes

Placement on the United Network for Organ Sharing deceased donor waitlist.

Analytical Approach

Age- and race-stratified waitlisting rates were compared. Multivariable Cox proportional hazards models, censored for death, examined the association between race and waitlisting, and included interaction term for race and age.

Results

Over a median follow-up period of 1 year, the proportion of non-Hispanic White and non-Hispanic Black patients waitlisted was 20.7% and 20.5%, respectively. In multivariable models, non-Hispanic Black patients were 14% less likely to be waitlisted (aHR, 0.86, 95% CI, 0.77-0.95). Relative differences between non-Hispanic Black and non-Hispanic White patients were different by age group. Non-Hispanic Black patients were 27%, 12%, and 20% less likely to be waitlisted than non-Hispanic White patients for ages 18-29 years (aHR, 0.73; 95% CI, 0.61-0.86), 50-64 (aHR, 0.88; 95% CI, 0.80-0.98), and 65-80 years (aHR, 0.80; 95% CI, 0.71-0.90), respectively, but differences were attenuated among patients aged 30-49 years (aHR, 0.89; 95% CI, 0.77-1.02).

Limitations

Race and ethnicity data is physician reported, residual confounding, and analysis is limited to non-Hispanic White and non-Hispanic Black patients.

Conclusions

Racial disparities in waitlisting exist between non-Hispanic Black and non-Hispanic White individuals and are most pronounced among younger patients with kidney failure. Results suggest that interventions to address inequalities in waitlisting may need to be targeted to younger patients with kidney failure.

Plain-Language Summary

Research has shown that patients from racial and ethnic minority groups and older patients have reduced access to transplant waitlisting relative to White and younger patients; nevertheless, how age impacts racial disparities in waitlisting is unknown. We compared waitlisting between non-Hispanic Black and non-Hispanic White patients with incident kidney failure, within age strata, using registry data for 439,455 US adults starting dialysis (18-80 years) during 2015-2019. Overall, non-Hispanic Black patients were less likely to be waitlisted and relative differences between the two racial groups differed by age. After adjusting for patient-level factors, the largest disparity in waitlisting was observed among adults aged 18-29 years. These results suggest that interventions should target younger adults to reduce disparities in access to kidney transplant waitlisting.

The impact of neighborhood social disadvantage on presentation and management of first-time hemodialysis access surgery patients

OBJECTIVES

The impact of social determinants of health on the presentation, management, and outcomes of patients requiring hemodialysis (HD) arteriovenous (AV) access creation have not been well-characterized. The Area Deprivation Index (ADI) is a validated measure of aggregate community-level social determinants of health disparities experienced by members living within a community. Our goal was to examine the effect of ADI on health outcomes for first-time AV access patients.

METHODS

We identified patients who underwent first-time HD access surgery in the Vascular Quality Initiative between July 2011 to May 2022. Patient zip codes were correlated with an ADI quintile, defined as quintile 1 (Q1) to quintile 5 (Q5) from least to most disadvantaged. Patients without ADI were excluded. Preoperative, perioperative, and postoperative outcomes considering ADI were analyzed.

RESULTS

There were 43,292 patients analyzed. The average age was 63 years, 43% were female, 60% were of White race, 34% were of Black race, 10% were of Hispanic ethnicity, and 85% received autogenous AV access. Patient distribution by ADI quintile was as follows: Q1 (16%), Q2 (18%), Q3 (21%), Q4 (23%), and Q5 (22%). On multivariable analysis, the most disadvantaged quintile (Q5) was associated with lower rates of autogenous AV access creation (OR, 0.82; 95% confidence interval [CI], 0.74-0.90; P < .001), preoperative vein mapping (OR, 0.57; 95% CI, 0.45-0.71; P < .001), access maturation (OR, 0.82; 95% CI, 0.71-0.95; P = .007), and 1-year survival (OR, 0.81; 95% CI, 0.71-0.91; P = .001) compared with Q1. Q5 was associated with higher 1-year intervention rates than Q1 on univariable analysis, but not on multivariable analysis.

CONCLUSIONS

The patients undergoing AV access creation who were most socially disadvantaged (Q5) were more likely to experience lower rates of autogenous access creation, obtaining vein mapping, access maturation, and 1-year survival compared with the most socially advantaged (Q1). Improvement in preoperative planning and long-term follow-up may be an opportunity for advancing health equity in this population.

Chronic Kidney Disease Burden in Low-Resource Settings: Regional Perspectives

The burden of chronic kidney disease (CKD) has increased exponentially worldwide but more so in low- and middle-income countries. Specific risk factors in these regions expose their populations to an increased risk of CKD, such as genetic risk with APOL1 among populations of West African heritage or farmers with CKD of unknown etiology that spans various countries across several continents to immigrant/indigenous populations in both low- and high-income countries. Low- and middle-income economies also have the double burden of communicable and noncommunicable diseases, both contributing to the high prevalence of CKD. The economies are characterized by low health expenditure, sparse or nonexistent health insurance and welfare programs, and predominant out-of-pocket spending for medical care. This review highlights the challenges in populations with CKD from low-resource settings globally and explores how health systems can help ameliorate the CKD burden.

Achieving Equity in Organ Transplantation: Recommendations for Action Based on the National Academies of Sciences, Engineering, and Medicine Report

The United States organ transplantation system has recently reached a historic milestone of a cumulative 1 million transplants. Despite this considerable success in providing life-saving organ transplants to patients with end organ failure, there are ample opportunities for improvement, particularly with regard to achieving equity. Recognizing this, Congress directed the National Institutes of Health to fund the National Academies of Sciences, Engineering, and Medicine in conducting a study on deceased donor organ procurement, allocation, and distribution, recommending ways to improve equity and accountability. The National Academies of Sciences, Engineering, and Medicine study committee's report, Realizing the Promise of Equity in the Organ Transplantation System , reached multiple conclusions and agreed on 14 recommendations for action that can be grouped into 3 areas: (1) achieving equity, (2) improving system performance, and (3) increasing the utilization of available organs. Here, we review overarching areas for improvement, highlighting key recommendations, and suggest implementing actions.

The impact of COVID-19 on kidney transplant care

The SARS-CoV-2 virus precipitated the coronavirus 2019 (COVID-19) pandemic, which placed considerable strain on healthcare systems and necessitated immediate and rapid alterations in the delivery of healthcare. In the transplant population, COVID-19 directly impacts an inherently vulnerable population in the setting of immunosuppression and co-morbidities, but also further complicates the clinical evaluation and management of kidney transplant candidates and recipients in a strained healthcare environment being challenged by the pandemic. Many transplant centers around the world saw mortality rate spikes in organ recipients related to COVID-19, and changes in care delivery abound. This review evaluates the care of the kidney transplant patient through all phases of the process including pre-operative evaluations, perioperative care, post-transplantation considerations, and how the global pandemic has changed the way we care for our patients.

Precision medicine implementation challenges for APOL1 testing in chronic kidney disease in admixed populations

Chronic Kidney Disease (CKD) is a public health problem that presents genetic and environmental risk factors. Two alleles in the Apolipoprotein L1 (APOL1) gene were associated with chronic kidney disease; these alleles are common in individuals of African ancestry but rare in European descendants. Genomic studies on Afro-Americans have indicated a higher prevalence and severity of chronic kidney disease in people of African ancestry when compared to other ethnic groups. However, estimates in low- and middle-income countries are still limited. Precision medicine approaches could improve clinical outcomes in carriers of risk alleles in the Apolipoprotein L1 gene through early diagnosis and specific therapies. Nevertheless, to enhance the definition of studies on these variants, it would be necessary to include individuals with different ancestry profiles in the sample, such as Latinos, African Americans, and Indigenous peoples. There is evidence that measuring genetic ancestry improves clinical care for admixed people. For chronic kidney disease, this knowledge could help establish public health strategies for monitoring patients and understanding the impact of the Apolipoprotein L1 genetic variants in admixed populations. Therefore, researchers need to develop resources, methodologies, and incentives for vulnerable and disadvantaged communities, to develop and implement precision medicine strategies and contribute to consolidating diversity in science and precision medicine in clinical practice.