Date of Award

Fall 2025

Language

English

Embargo Period

12-10-2027

Document Type

Dissertation

Degree Name

Doctor of Public Health (DrPH)

College/School/Department

Department of Epidemiology and Biostatistics

Program

Epidemiology

First Advisor

Melissa Tracy

Committee Members

Tomoko Udo, Benjamin Fisher

Keywords

cardiac arrest, opioid, EMS, COVID-19, disparities

Subject Categories

Clinical Epidemiology | Community Health and Preventive Medicine | COVID-19 | Epidemiology | Health Services Research | Other Public Health

Abstract

Out-of-hospital cardiac arrest (OHCA) remains a leading cause of mortality in the United States, with opioid-associated OHCA (OA-OHCA) presenting unique challenges, including during the COVID-19 pandemic. Understanding individual-, community-, and policy-level factors shaping risk for OA-OHCA, as well as survival and resuscitation outcomes after OA-OHCA, is essential in improving care and guiding interventions.

Using the 2018-2023 National EMS Information System (NEMSIS) dataset, I conducted multilevel logistic regression models and comparative interrupted time series (CITS) analyses to evaluate differences between OA-OHCA and non-OA-OHCA cases. Patient-, incident-, EMS-, community-, and state-level covariates were examined, including demographic characteristics, resuscitation practices, county-level social vulnerability (SVI), and state naloxone laws. Random intercepts accounted for clustering at the EMS agency level. Outcomes included return of spontaneous circulation (ROSC) and positive end-of-event status (presumptively alive). Time-series analyses assessed weekly rates of OHCA, ROSC, and survival before and during the COVID-19 pandemic.

Age was the strongest individual-level factor distinguishing OA-OHCA patients from non-OA-OHCA patients. Unadjusted ROSC was higher in OA-OHCA than non-OA-OHCA patients (28.3% vs. 25.3%), though this difference was largely explained by initial rhythm and bystander intervention. In fully adjusted models, OA-OHCA patients had similar odds of survival to non-OA-OHCA patients (aOR = 1.03; 95% CI [1.01-1.06]). Among OA-OHCA patients, witnessed status, shockable rhythm, and shorter EMS response time strongly predicted ROSC and survival. Arrests that occurred in counties with higher uninsured rates had lower survival odds. Comparative interrupted time series showed that both OA-OHCA and non-OA-OHCA rates increased significantly during the COVID-19 pandemic, while ROSC and survival declined modestly.

Both individual clinical characteristics and community-level disadvantage significantly influenced outcomes. The COVID-19 pandemic disrupted OHCA incidence, resuscitation, and survival trends, with greater negative impact on non-OA-OHCA cases. Policies supporting bystander intervention, EMS response, and naloxone access may mitigate disparities and improve outcomes for OHCA cases, especially in the event of future public health emergencies.

License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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Available for download on Friday, December 10, 2027

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