County-Level Social Vulnerability and Emergency Department Visits for Firearm Injuries

10 U.S. Jurisdictions, January 1, 2018-December 31, 2021

Miriam E. Van Dyke, PhD; May S. Chen, PhD; Michael Sheppard, MS; J. Danielle Sharpe, PhD; Lakshmi Radhakrishnan, MPH; Linda L. Dahlberg, PhD; Thomas R. Simon, PhD; Marissa L. Zwald, PhD

Disclosures

Morbidity and Mortality Weekly Report. 2022;71(27):873-877. 

In This Article

Abstract and Introduction

Introduction

At least 100,000 persons in the United States experience a fatal or nonfatal firearm injury each year.* CDC examined rates of firearm injury emergency department (ED) visits by community social vulnerability using data from CDC's Firearm Injury Surveillance Through Emergency Rooms (FASTER) program. ED visit data, shared with CDC's National Syndromic Surveillance Program (NSSP)§ during 2018–2021, were analyzed for 647 counties in 10 FASTER-funded jurisdictions. County-level social vulnerability data were obtained from the 2018 Social Vulnerability Index (SVI).** Rates of ED visits for firearm injuries (number of firearm injury ED visits per 100,000 ED visits) were calculated across tertile levels of social vulnerability. Negative binomial regression models were used to estimate rate ratios (RRs) and associated 95% CIs comparing rates of ED visits across social vulnerability levels. During 2018–2021, compared with rates in counties with low overall social vulnerability, the firearm injury ED visit rate was 1.34 times as high in counties with medium social vulnerability and 1.80 times as high in counties with high social vulnerability. Similar patterns were observed for the SVI themes of socioeconomic status and housing type and transportation, but not for the themes of household composition and disability status or racial and ethnic minority status and language proficiency. More timely data†† on firearm injury ED visits by social vulnerability can help identify communities disproportionately experiencing elevated firearm injury rates. States and communities can use the best available evidence to implement comprehensive prevention strategies that address inequities in the social and structural conditions that contribute to risk for violence, including creating protective community environments, strengthening economic supports, and intervening to reduce harms and prevent future risk (e.g., with hospital-based violence intervention programs).[1,2]

In 2021, CDC's FASTER program was established to provide more timely and comprehensive data on firearm injuries at the state and local levels than were available through traditional data sources. CDC analyzed ED visit data during January 1, 2018–December 31, 2021, for 647 counties in 10 FASTER-funded jurisdictions. Aggregated data were shared through CDC's NSSP platform.[3] The 10 jurisdictions included in this analysis reported data on a minimum of 75% of ED visits occurring within their jurisdictions, including a minimum of 90% of visits from Level 1–3 trauma centers.§§ Initial firearm injury encounters (including those classified as unintentional, intentional self-harm, assault, legal intervention, terrorism, and undetermined intent) were identified using a syndrome definition including diagnosis codes and chief complaint text fields (Supplementary Box, https://stacks.cdc.gov/view/cdc/118752).

Data on county-level social vulnerability were obtained from the 2018 SVI, which uses U.S. Census Bureau American Community Survey 2014–2018 5-year data¶¶ estimates for 15 population-based county-level sociodemographic indicators to form an overall social vulnerability metric, as well as four additional focused metrics representing themes of socioeconomic status, household composition and disability, racial and ethnic minority status and language proficiency, and housing type and transportation. The SVI includes ranked scores ranging from 0–1 applied to 3,142 counties in the United States.

Counties in the 10 FASTER-funded jurisdictions were categorized into tertiles (low, medium, high) of social vulnerability for the overall SVI, the SVI themes, and the individual indicators of each SVI theme, with higher values representing higher levels of social vulnerability. Crude rates of firearm injury ED visits (number of ED visits for firearm injuries per 100,000 ED visits) were calculated for each level of social vulnerability. A total of 647 (99.2%) of 652 counties sharing data with NSSP in the 10 jurisdictions had data on ED visits and the SVI, and were included in the analyses. Negative binomial regression models including fixed effects for jurisdictions were fit to estimate RRs and associated 95% CIs comparing rates among high and medium social vulnerability counties with those in low social vulnerability counties across the overall SVI, separate SVI themes, and individual SVI indicators.*** Regression analyses were conducted using SAS software (version 9.4; SAS Institute). SVI tertiles were included in the models as categorical variables. This activity was reviewed by CDC and was conducted consistent with applicable federal law and CDC policy.†††

During 2018–2021, the overall crude firearm injury ED visit rate among the 10 jurisdictions was 74 per 100,000 ED visits, with low, medium, and high social vulnerability counties experiencing rates of 55, 77, and 92 firearm injury ED visits per 100,000 ED visits, respectively. Compared with counties with low overall social vulnerability, rates of firearm injury ED visits were 1.34 and 1.80 times as high in counties with medium and high overall social vulnerability, respectively (Table). Similar patterns were observed for the SVI theme of socioeconomic status, with rates of firearm injury ED visits higher among counties with medium (RR = 1.27) and high (RR = 1.61) vulnerability compared with counties with low social vulnerability. This pattern was apparent for all four indicators of socioeconomic status, with the most pronounced differences in firearm injury ED visit rates observed when comparing SVI tertiles across the poverty indicator.

For the housing type and transportation theme, rates of firearm injury ED visits were also higher among medium (RR = 1.32) and high (RR = 1.75) social vulnerability counties compared with low social vulnerability counties. This pattern was apparent for two of five indicators constituting the theme: percentage of persons living in group quarters and percentage of households with no vehicle access.

Although ED visit rates were not higher in medium and high social vulnerability counties for the two SVI themes of household composition and disability status and racial and ethnic minority status and language proficiency, among specific indicators for each, rates were higher among counties with higher percentages of single-parent households and persons identifying as a racial or ethnic minority; rates were lower among counties with higher percentages of persons aged ≥65 years.

*https://www.cdc.gov/injury/wisqars/index.html
https://www.cdc.gov/violenceprevention/firearms/funded-surveillance.html
§Analyses were limited to ED encounters. NSSP is a collaboration among CDC; local and state health departments; and federal, academic, and private sector partners. Electronic patient encounter data are collected from EDs, urgent and ambulatory care centers, inpatient health care settings, and laboratories. https://www.cdc.gov/nssp/index.html
The 10 FASTER-funded jurisdictions were the District of Columbia, Florida, Georgia, New Mexico, North Carolina, Oregon, Utah, Virginia, Washington, and West Virginia.
**https://www.atsdr.cdc.gov/placeandhealth/svi/index.html
†† Improving Data Infrastructure to Reduce Firearms Violence PDF
§§ https://www.amtrauma.org/page/traumalevels
¶¶ https://www.census.gov/programs-surveys/acs/technical-documentation/table-and-geography-changes/2018/5-year.html
***The number of facilities sharing data with NSSP can vary over time and potentially influence ED visit trends. Although this study used a cross-sectional analysis using data aggregated across years and did not examine trends, sensitivity analyses were conducted by restricting to facilities consistently reporting informative data (specifically, facilities with a coefficient of variation ≤40 and average number of weekly discharge diagnoses with useful information of ≥75 through the analysis period; average number of weekly discharge diagnoses with useful information was not applied to facilities in the District of Columbia). Results from the sensitivity analyses were similar to results presented in this report, which analyzed data from all facilities sharing data with NSSP in the 10 FASTER-funded jurisdictions during the study period.
†††45 C.F.R. part 46.102(l)(2), 21 C.F.R. part 56; 42 U.S.C. Sect. 241(d); 5 U.S.C. Sect. 552a; 44 U.S.C. Sect. 3501 et seq.

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