Living in socioeconomically disadvantaged neighborhoods has long been associated with poor health outcomes, a connection that has been well documented across numerous chronic disease studies. However, new research emerging from the University of California, San Francisco, presented at the ATS 2025 International Conference, reveals that commonly used tools to measure neighborhood disadvantage may not accurately capture the true socioeconomic realities in certain high-cost urban settings. This study, spearheaded by pulmonologist Dr. Kathryn Sullivan, delved into how two leading socioeconomic indices, the Area Deprivation Index (ADI) and the Healthy Places Index (HPI), perform in predicting mortality among critically ill sepsis patients in the San Francisco Bay Area.
The ADI has been a dominant metric in public health and health services research due to its comprehensive assessment of neighborhood-level socioeconomic disadvantage. It combines multiple factors including income, education, employment, and particularly housing characteristics, to rank neighborhoods on a deprivation scale. This index also plays a pivotal role in healthcare funding decisions; for example, the Centers for Medicare and Medicaid Services (CMS) use the ADI to allocate resources to accountable care organizations. However, emerging concerns question whether the ADI’s reliance on home values may inadvertently skew its assessments in regions where housing costs are disproportionately high compared to other socioeconomic indicators.
In this latest investigative study, researchers scrutinized data from nearly 900 critically ill patients admitted with sepsis through two emergency departments in San Francisco. By geocoding patients’ home addresses, the team applied both the ADI and the HPI to classify neighborhood disadvantage and then correlated these indices with patient mortality outcomes. Notably, the HPI—an index developed in California that incorporates a broader range of community health determinants including economic, social, and environmental factors—outperformed the ADI in predicting in-hospital death risk.
What stands out starkly from the findings is the ADI’s failure to recognize certain San Francisco neighborhoods as socioeconomically disadvantaged. Despite well-documented struggles with poverty and limited resource access in these areas, ADI rankings erroneously classified them as some of the most advantaged in the nation. The distortion appears to stem primarily from the ADI’s heavy weighting on home values, which are inflated by the Bay Area’s high housing market. This phenomenon masks other signs of deprivation like employment instability, housing insecurity, and limited environmental assets, which the HPI includes in its composite scoring.
The implications of this misclassification are profound for public health and clinical care. For critically ill sepsis patients, mortality risk is known to be influenced by social determinants of health, including neighborhood disadvantage, which impacts access to timely care, prevalence of comorbidities, and post-discharge support. By failing to accurately identify patients from disadvantaged communities, healthcare systems utilizing ADI-based models risk under-prioritizing vulnerable populations who may require more aggressive care coordination and resource allocation.
Dr. Sullivan emphasized that while the ADI remains a validated and valuable measure on national and statewide levels, its utility diminishes in unique urban settings characterized by high economic disparities combined with exorbitant housing costs. “This misalignment urges us to critically evaluate the tools we use and tailor them to reflect the socioeconomic landscape more precisely,” she noted. The research underscores that the Healthy Places Index, by capturing a more nuanced set of socioeconomic and environmental factors, aligns more closely with actual patient outcomes in this context.
Beyond unveiling the limitations of the ADI in high-cost urban centers, the study advances the broader discourse on how social determinants of health profoundly shape outcomes in acute, critical illnesses like sepsis. Traditionally, most investigations have focused on chronic diseases where long-term lifestyle and environmental exposures interplay. However, this study illuminates how neighborhood context can also influence the trajectory of sudden severe illness, especially when social resources and healthcare access are constrained.
Another essential takeaway from the study is the urgent need to refine socioeconomic indices employed in healthcare research and resource distribution. Dr. Sullivan and her team advocate for continuous reevaluation and localization of these tools, suggesting that a one-size-fits-all approach may lead to inaccuracies and unintended inequities in care delivery. Future investigations are planned to probe the underlying reasons for the ADI’s shortcomings in the Bay Area further and to test these findings in more rural settings where demographic and economic structures differ significantly.
Moreover, the study highlights how incorporating comprehensive, multidimensional indices like the HPI into clinical risk stratification frameworks could improve predictive accuracy and help health systems identify high-risk populations more effectively. Such improved measurement could ultimately support tailored interventions and policies aimed at mitigating health disparities and reducing mortality in vulnerable groups.
As healthcare becomes increasingly data-driven and precision-oriented, understanding where and why socioeconomic tools falter enables researchers and policymakers to recalibrate existing models to reflect the complex realities of diverse populations. The tension between national-level applicability and local accuracy presents a challenging yet critical dimension of social determinants research.
In summary, this pioneering investigation reveals that the widely used Area Deprivation Index may not sufficiently capture neighborhood disadvantage in high-cost urban areas like San Francisco. In contrast, the Healthy Places Index offers a more representative socioeconomic portrait that correlates more robustly with mortality risk in critically ill sepsis patients. These findings not only question the adequacy of current measurement approaches but also signal the necessity for adaptable, multifaceted tools to inform equitable healthcare allocation and improve outcomes in vulnerable populations.
By bridging epidemiologic insights with clinical outcomes, the research led by Dr. Sullivan sheds light on the intersection of social environment and acute critical illness and invites a rethinking of how socioeconomic data are integrated into health systems. As the medical community strives to unravel the social determinants embedded within regional contexts, such nuanced approaches promise to refine risk prediction, optimize care delivery, and ultimately save lives.
Subject of Research: Socioeconomic measures (Area Deprivation Index and Healthy Places Index) and their association with mortality in critically ill sepsis patients.
Article Title: Neighborhood Health Measured by the Healthy Places Index (HPI), but Not by the Area Deprivation Index (ADI), Is Associated with Mortality for Critically Ill Sepsis Patients in the San Francisco Bay Area
News Publication Date: Wednesday, May 21, 2025
Web References: https://www.atsjournals.org/doi/abs/10.1164/ajrccm.2025.211.Abstracts.A7364
Image Credits: Kathryn Sullivan, MD
Keywords: Sepsis, Socioeconomic Determinants of Health, Area Deprivation Index, Healthy Places Index, Critical Illness, Mortality Risk, Health Disparities
