Geospatial Analysis of Opioid-Related Outcomes Across Riverside County ZIP Codes and Associations With Social Determinants of Health.

Background This study evaluated ZIP-code-level variation in opioid-related emergency department visits, hospitalizations, and overdose deaths across Riverside County, California, and examined associations with community-level social determinants of health (SDOH), operationalized using Healthy Places Index (HPI) domains and indicators. Identifying ZIP codes with elevated opioid-related outcome severity may help prioritize interventions such as naloxone distribution, mobile outreach, treatment linkage, and community education. Methods Publicly available data from the California Department of Public Health was analyzed to capture opioid-related deaths, hospitalizations, and emergency department visits in Riverside County. Datasets were cleaned and integrated using R (R Foundation for Statistical Computing, Vienna, Austria). A normalized severity score (NSS) was calculated for each ZIP code by combining mortality, hospitalizations, and ED visits into a composite min-maxed score from 0-1. Geographic variation was visualized using an interactive choropleth map developed with the Leaflet package. Multivariable linear regression was used to evaluate associations between the NSS and community-level HPI domains and indicators, including measures of economic conditions, housing, transportation, employment, and homeownership. Results NSS values varied substantially across Riverside County ZIP codes. In multivariable analyses, lower Economic and Transportation HPI domain scores and lower employment and homeownership indicators were associated with higher NSS values. Conclusions Higher NSS values were associated with lower Economic and Transportation HPI domain scores, as well as lower employment and homeownership indicators. Integrating fatal and non-fatal outcomes into the NSS provides a broader descriptive measure of community-level opioid burden than examining mortality alone. These geospatial findings may help guide location-specific community outreach and preventive interventions in ZIP codes with higher NSS values. Additionally, the geographic variation observed across Riverside County ZIP codes is broadly consistent with national evidence of spatial variation in opioid-related morbidity and mortality.