The Association of Racial Residential Segregation and Long-Term Outcomes after Out-Of-Hospital Cardiac Arrest Among Medicare Beneficiaries

BackgroundRacial residential segregation in the US is associated with poor health outcomes across multiple chronic conditions including cardiovascular disease. However, the national impact of racial residential segregation on out-of-hospital cardiac arrest (OHCA) outcomes after initial resuscitation remains poorly understood. We sought to characterize the association between measures of racial and economic residential segregation at the ZIP code level and long-term survival after OHCA among Medicare beneficiaries. MethodsIn this retrospective cohort study, utilizing Medicare fee-for-service claims data from 2013-2015, our primary predictor was the index of concentration at the extremes (ICE), a measure of racial and economic segregation. The primary outcomes were death at 1 and 3 years. Using random-effects Cox proportional hazards models, including a shared frailty term to account for clustering at the hospital level, we estimated hazard ratios across all three types of ICE measures for each outcome while adjusting for beneficiary demographics, treating hospital characteristics, and index hospital procedures. ResultsWe identified 29,847 OHCA claims for beneficiaries who survived to discharge after an OHCA. Mean beneficiary age was 75 years (SD 8); 40.1% were female, 80% White and 15.2% Black. Overall crude survival for the cohort was 54% (n=16,129) at 1 year and 40.8% (n= 12,189) at 3 years. In fully adjusted models we found a decreased hazard of death in beneficiaries residing in the most racially and economically privileged ZIP codes (Q5) compared to the least privileged areas (Q1) across all three ICE measures (race: HR:0.84; CI 0.79-0.88, income: HR 0.76; CI 0.73-0.81, race + income: HR 0.78; CI 0.74-0.83) ConclusionWe found a decreased hazard of death for those residing in predominately White and higher income ZIP codes as compared to majority Black and lower income ZIP codes when using validated measures of racial and economic segregation. Future work will need to more closely examine the causal pathways and mechanisms related to disparities in outcomes after OHCA to better understand the impacts of spatial and living environments on long-term outcomes.