Neighborhood Segregation Linked to Racial Disparities in Access to Live Donor Kidney Transplantation

Residential and transplant center neighborhood segregation may impact transplant candidates’ access to live donor kidney transplantation based on their race, according to findings from a recent cohort study.¹

Published in JAMA Internal Medicine, results showed candidates listed at transplant centers in high-segregation neighborhoods had lower access to live donor kidney transplantation, especially in predominantly minority neighborhoods, relative to their counterparts listed at transplant centers in low-segregation neighborhoods.¹

According to the Organ Procurement and Transplantation Network, more than 42,800 organ transplants were performed in 2022 – notably, kidney transplants exceeded 25,000 for the first time, setting an annual record and marking a 3.4% increase from 2021.² A kidney from a living donor may have several advantages over a kidney from a deceased donor, including less chance of rejection and longer duration of kidney functionality, although access to living donor kidney transplantation is fragmented.³

“Although the detrimental effects of structural racism on health and the role of social determinants of health on access to [live donor kidney transplantation] are well documented, the specific mechanisms that contribute to these disparities remain underexplored,” wrote Mara McAdams DeMarco, PhD, associate professor in the departments of surgery and population health at New York University Grossman School of Medicine, and colleagues.¹

To assess the impact of residential and transplant center segregation on patients’ access to living donor kidney transplantation, investigators enrolled adult first-time kidney transplant candidates who underwent a live donor transplant between January 1, 1995, and December 31, 2021. Their race and ethnicity were determined based on variables provided in the Organ Procurement and Transplantation Network forms. Candidates with missing clinical or demographic data, patients who were listed and underwent kidney transplantation on the same day, or those who were listed and died on the same day were excluded.¹

Investigators measured segregation using the Multigroup Entropy Index, also known as the Theil H method, calculating segregation tertiles in zip code tabulation areas based on 5-year estimates from the American Community Survey. The calculation involved measuring the level of diversity within a zip code tabulation area and assessing the distribution of racial and ethnic groups across neighborhoods of the respective city, reflecting the heterogeneity in neighborhood racial and ethnic composition.¹

Investigators categorized candidates’ segregation scores into tertiles, defining residential neighborhood segregation as low (≤4.2), medium (>4.2 and ≤12.4), and high (>12.4), and transplant center neighborhood segregation as low (≤11.6), medium (>11.6 and ≤18.5), and high (>18.5). To quantify the likelihood of live donor kidney transplantation by neighborhood segregation, cause-specific hazard models were adjusted for individual-level and neighborhood-level factors and included an interaction between segregation tertiles and race.¹

In total, 162,587 kidney transplant candidates were included in the study. The median follow-up time for each participant was 1.9 (Interquartile range [IQR], 0.6-3.0) years, the mean age was 51.6 (Standard deviation [SD], 13.2) years, 65,141 (40.1%) were female, and 80,023 (49.2%) were Black.¹

Investigators noted high-segregation residential neighborhoods were characterized by a greater proportion of Black candidates relative to low-segregation residential neighborhoods (69.2% vs 30.2%; P <.001). Among Black transplant candidates, living in a high-segregation neighborhood was associated with 10% (adjusted hazard ratio [aHR], 0.90; 95% CI, 0.84-0.97) lower access to live donor kidney transplantation relative to residing in a low-segregation neighborhood. However, no such association was observed among White candidates.¹

Compared to White candidates residing in low-segregation neighborhoods, Black candidates residing in high-segregation neighborhoods had 59% (aHR, 0.41; 95% CI, 0.39-0.43; P <.001) lower access to a live donor kidney transplant. Of note, both Black (P = .001) and White (P = .004) candidates had a lower 3-year cumulative incidence of living donor transplantation when listed at a transplant center in a high-segregation neighborhood.¹

After adjustment, candidates listed at transplant centers located in high-segregation neighborhoods had significantly lower access to living donor transplantation compared to those in low-segregation transplant center neighborhoods (aHR, 0.81; 95% CI, 0.78-0.84), and the magnitude of this association was similar regardless of candidate race. Within high-segregation transplant center neighborhoods, candidates listed in predominantly minority neighborhoods had 17% lower access to living donor transplantation relative to candidates listed in predominantly White neighborhoods (aHR, 0.83; 95% CI, 0.75-0.92).¹

“This national cohort study highlights the considerable role of racial and ethnic segregation in both the candidate’s residential neighborhood and the transplant center’s neighborhood in shaping access to LDKT,” investigators concluded.¹

References:

1. ^{Li Y, Menon G, Kim B, et al. Neighborhood Segregation and Access to Live Donor Kidney Transplantation. JAMA Intern Med. doi:10.1001/jamainternmed.2023.8184}
2. ^{Organ Procurement and Transplantation Network. 2022 organ transplants again set annual records; organ donation from deceased donors continues 12-year record-setting trend. January 10, 2023. Accessed February 19, 2024. https://optn.transplant.hrsa.gov/news/2022-organ-transplants-again-set-annual-records-organ-donation-from-deceased-donors-continues-12-year-record-setting-trend/}
3. ^{American Kidney Fund. Deceased donor kidney transplants. April 18, 2023. Accessed February 19, 2024. https://www.kidneyfund.org/kidney-donation-and-transplant/deceased-donor-kidney-transplants}