BACKGROUND: In St. Louis County, Missouri, there were over 32,000 emergency department (ED) visits for asthma between 2010 and 2014. Severe asthma attacks can require emergency care or even be life threatening. Asthma can be managed with medication and avoiding triggers, yet socioeconomic factors can be a barrier to preventative care. The Social Vulnerability Index (SVI), created by the Agency for Toxic Substances and Disease Registry (ATSDR) groups social factors from U.S. Census data into themes. This study explored the SVI themes to capture synergistic effects of multiple socioeconomic factors related with ED visits for asthma.
METHODS: ED visits for Asthma—principal diagnosis of ICD-9 code 493—among St. Louis County residents, 2010–2014, including census tract, were obtained from the Missouri Department of Health and Senior Services (DHSS). Census tract rates age-adjusted to 2000 US population; used American Community Survey (ACS) 5-year estimates (2009-2013). The SVI 2014 Tract Shapefile for Missouri State was accessed online. Census tracts are ranked based on percentiles—higher values are higher vulnerability. SVI themes: Socioeconomic Status (income, poverty, employment, education); Household Composition (age <18 years or >=65 years, single parent, disability); Race/Ethnicity/Language (race, ethnicity, and English-language proficiency); Housing/Transportation (housing structure, crowding, vehicle access). Maps created using ESRI ArcMap version 10.3 to compare geographic patterns of SVI themes by census tract with ED visit rates for asthma.
RESULTS: During 2010-2014, ED visit rates for asthma ranged from 6.7 per 1,000 population to 52.6. The highest burden of ED visits for asthma were among residents living in census tracts in North County. The highest vulnerability for the Socioeconomic Status and Household Composition themes were in the North County. Some of the highest vulnerability census tracts for the Housing/Transportation theme resembled areas of high ED visit rates for asthma. However, the highest vulnerability for the Race/Ethnicity/Language theme did not correspond to as well with ED visits for asthma.
CONCLUSIONS: In St. Louis County, census tracts with the highest vulnerability from socioeconomic status and household composition have the highest rates of ED visits for asthma. Areas of low income, high unemployment, or high proportion of single-parent households may lack adequate resources to support proper preventative care for asthma, and in turn, increase ED visits. These findings have implications for monitoring health equity in chronic disease epidemiology.