Where your liver lives matters: How neighborhoods shape transplant outcomes

Social determinants of health (SDOH), “the non-medical factors that influence health outcomes,” are shaped by broader systems and play a crucial role in mediating inequities in liver transplant access and outcomes.1 Conceptualizing the influence of SDOH on liver-related health and disease is challenging, given the complex interplay of social and structural factors. Neighborhood-level disadvantage stems from larger structural issues such as systemic racism, which can manifest through zoning, housing access, and neighborhood segregation.2 Using deprivation indices for individuals living near each other allows for exploration through a place-based approach to neighborhood-level effects on health outcomes. In a study published in Liver Transplantation, Forman et al3 report the findings of a retrospective study assessing the association between neighborhood socioeconomic deprivation and mortality and graft survival among adult recipients of liver transplants.3 The Social Deprivation Index (SDI) measures disadvantage using 7 demographic American Community Survey characteristics related to income, education, employment, housing, and transportation across geographic areas.4 Geographic areas vary in specificity, from highly granular “block groups” to broader zip code tabulation areas. The SDI maps to “census tracts,” which are subdivisions of counties. We offer potential examples of how neighborhood factors captured in the SDI could influence outcomes for recipients of liver transplants (Table 1). Other indices such as the Area Deprivation Index, Social Vulnerability Index, and Neighborhood Deprivation Index may capture similar mechanisms.5 Researchers should carefully choose the appropriate indices based on the study’s context and objectives and construct robust frameworks to explore the interconnectedness of specific factors in shaping posttransplant outcomes.5 TABLE 1 - Potential mechanisms for neighborhood characteristics in the SDI that impact transplant recipient outcomes SDI domain SDI description Potential mechanism from neighborhood to transplant outcomes 1. Income % population <100% FPL Poverty-stricken and disenfranchised communities → less green/blue spaces and more food deserts → poor health and nutrition 2. Employment % nonemployed for population 16–64 y 3. Education % population ≥25 y w/ <12 y education Lower health literacy of community and support system during recovery after transplant 4. Renting % households living in renter-occupied housing Less wealth-building and neighborhood investment → Fewer community resources 5. Crowding % households living in crowded housing units ↑infectious risk in the community → illness and hospitalizations (eg, COVID) 6. Single parent % single-parent families w/ dependents <18 y Social support systems with ↑stress and allostatic load during recovery 7. Transportation % households w/ no vehicle Limited assistance from the community for follow-up visits or emergencies Abbreviations: FPL, federal poverty level; SDI, social deprivation index. The authors analyzed data from 80,612 adult recipients of liver transplants from 2008 to 2021, using multivariable models to evaluate the relationship between SDI and 5-year patient and graft survival. Five-year graft survival (76.5%) and patient survival (78.7%) in high SDI (more deprived) areas were statistically significantly lower compared with graft survival (78.3%) and patient survival (80.5%) in low SDI areas. Recipients in the highest deprivation quintile had a 6% higher risk of mortality and graft failure compared with those in the lowest quintile, especially in the first year after transplantation. In addition, conditional on surviving 1 year after transplant, younger recipients (18–39 y old) in the highest deprivation quintile areas had worse outcomes compared with those in the lowest quintile. These findings underscore the long-term effects of neighborhood socioeconomic deprivation on transplant success. While the study provides valuable insights and was a tremendous analytical undertaking, some limitations should be acknowledged. Using the SDI as an index measure to coalesce a heterogeneous group of neighborhood-level components is an important first step, and further investigation into the specific variables is warranted. Understanding how factors such as education or transportation may impact transplant outcomes can help in developing interventions. In addition, this study was limited by national registry transplant data only providing zip codes, and this prevented more specific census tract linkage with SDI, potentially introducing misclassification bias regarding the SDI exposure group. Nevertheless, Forman and colleagues captured important insights into key health equity issues at the individual and neighborhood levels for a large population. Shifting from describing inequities to mobilizing interventions is a crucial next step. Northwestern Medicine has established effective models through the Hispanic Transplant Program and African American Transplant Access Program, addressing barriers to transplant access by offering culturally competent resources and care.6,7 Incorporating SDOH assessments into pretransplant and posttransplant care plans could also aid in identifying patients at higher risk of poor outcomes and provide personalized support. At a policy level, funding could be directed toward programs that support socioeconomically disadvantaged communities, including transportation assistance, housing support, and nutrition programs. Future studies could assess the sustainability and effectiveness of targeted interventions on transplant outcomes in the long term. Addressing disparities in liver transplant outcomes requires understanding and targeting SDOH at multiple levels. The study by Forman and colleagues highlights the significant impact of neighborhood deprivation on posttransplant survival rates, necessitating holistic strategies to mitigate these inequities. Policymakers, health care providers, and researchers must collaborate to develop and implement strategies that reduce disparities in liver transplant outcomes for recipients from socioeconomically deprived areas.