Population Level Surveillance of Domestic Violence Using the National Emergency Medical Services Information System (NEMSIS)

Background and purpose: Violence in the home, including intimate partner violence, child abuse, and elder abuse, is pervasive in the United States. An informatics approach to understanding the health burden of domestic violence that allows automated analysis of administrative data to release more timely and localized data would assist social workers to identify geographic and demographic populations of need and design tailored interventions for local communities. Methods: This study explores the 2019 National Emergency Medical Services Information System (NEMSIS) as a potential annual data source for future automation and use in domestic violence surveillance. An algorithm was used to identify individuals who utilized emergency medical services (EMS) for a physical assault that occurred in a private residence (n= 176,931). Descriptive analyses were conducted to define the identified population and the disposition of patients. A logistic regression was preformed to predict which characteristics were associated with consistent identification of domestic assault by the Emergency Medical Technician (EMT) on scene and EMS dispatcher. Results: The NEMSIS sample was majority female (52.2%), White (44.7%), urban (85.5%), 21-29 years old (24.4%), and from the South Atlantic region (26.4%). EMS usage was highest during the summer. A disproportionate number of men were found dead on scene (74.5% male), and female patients represented a higher proportion of individuals who refused treatment (57.8%) or were treated and then released against medical advice (58.4%). Individuals under 18 and over 65 had higher odds of being consistently identified as experiencing domestic assaults than those 21-49 and women had lower odds of consistent identification than men. Conclusions and Implications: NEMSIS data mirrors trends in national law enforcement data, with numerically more assaults occurring against people in their 20s, women, urban, and White individuals, while more men experience fatal assaults. Women were less likely to be consistently identified as domestic assault victims in the EMS data. More research is needed to determine if the definitions of domestic assault are not accurately capturing women’s experiences of violence in the home or if this points to women being more likely to recant an account of violence due to safety concerns. More work is needed to determine if the finding that women more frequently refuse care is related to a lack of gender-responsive care or due to gendered differences in the types of assault experienced, as women are more likely to experience simple assault than men. These data indicate an opportunity to systematically track domestic violence in communities and describe population-specific needs, however a more specific field to identify the type of domestic assault (i.e., intimate partner, older persons, child, familial) would provide more specialized counts to inform intervention planning is needed. Despite this limitation, the NEMSIS data demonstrate a unique opportunity for social workers to expand an existing data system to better track domestic violence in their communities.