Introduction

Intimate partner violence (IPV) is a public health problem that involves victimization by a current or former spouse or partner through the use of physical and/or sexual violence, psychological harm, and in some cases, stalking [1]. Recent estimates demonstrate that approximately 37% of women and 31% of men in the United States (US) have reported experiences of IPV in their lifetime [2]. Although studies have revealed similar population rates of IPV between rural and non-rural locales [3],[4],[5], rural IPV is perpetrated at a higher frequency within relationships and with greater severity [6]. In rural areas, perpetrators of IPV are more likely to use weapons [7] and intimate partner homicide rates are significantly higher compared to those in urban and suburban locales [8]. Furthermore, those experiencing IPV in rural areas access medical systems and utilize formal and informal resources less frequently [9],[10]. Social and geographic isolation, increased travel times to receive shelter and treatment, and the presence of fewer social and medical support systems create significant challenges to the provision of adequate services for rural individuals exposed to IPV [5],[6],[11].

The culturally and geographically defined Appalachian region has one of the largest rural populations in the US (42% rural compared to 20% of US). Appalachia encompasses an area of about 205,000 square miles stretching along the spine of the Appalachian mountain range from southern New York to northern Mississippi [12]. Appalachian communities experience higher levels of economic distress characterized by lower income and educational attainment compared to those living in the non-Appalachian US [13]. Further, Appalachians have poorer health status, including higher rates of morbidity and mortality from chronic diseases, compared to individuals residing outside of the area [14],[15],[16]. The region also faces significant disparities related to mental health disorders and substance use [17] and higher death rates from prescription drug abuse [18] and motor vehicle crashes [19]. While these disparities are pronounced when compared to the rest of the US, there is substantial variation throughout Appalachia with central Appalachia continuing to face significant disparities compared to northern and southern Appalachia [14]. Appalachia also has a history of an extreme shortage of health care providers and appropriate health services [13],[20]. Therefore, examining social and contextual factors associated with health behaviors and outcomes among Appalachian populations, in specific, versus those with rural populations in general, is critical for the development of a comprehensive picture of localized Appalachian health disparities to guide the design and implementation of future interventions to reduce IPV.

Unfortunately, limited information is available regarding the extent and nature of IPV in Appalachia that is separate from what has been published about IPV in other rural regions. A recent population-based study of the prevalence of rural IPV conducted in 16 states found no significant difference in 12-month or lifetime IPV prevalence between those living in rural versus non-rural areas of the US, but only two of the included states have counties that lie within the Appalachian region [3]. Further investigation is warranted, as Appalachian populations—and in particular those residing in rural areas of Appalachia—may face double or triple disadvantage due to the intersection of geographical, sociocultural, and economic conditions unique to the region. These compounding levels of risk, coupled with the presence of fewer health resources [3],[4],[5], may leave this population inherently vulnerable to the acute and long-term physical and mental health consequences of IPV.

IPV-specific information is often captured from community, criminal justice, shelter, and healthcare settings. Although data from community samples allow for epidemiological study of the prevalence and incidence of various forms of IPV among the general US population or within specific communities, estimates are typically provided for single sites or at state or national levels. Data collected from criminal justice surveillance and shelter settings may include cases of IPV that involve law enforcement or criminal acts (eg, intimate partner homicide, use of weapons) and among populations who have left abusive or unsafe situations, respectively, but may not be generalizable to other situations involving IPV. Furthermore, these sources lack reliable data on the health impacts associated with IPV. Individuals exposed to IPV generally have more frequent contact with the healthcare system and higher costs for medical and mental health services than those who have not experienced IPV [21–24]. In fact, abused women are seen in the healthcare setting more often than in shelters or within the criminal justice system, making hospitalization records and surveillance data from health systems an important source of information on IPV.

Data on IPV-related hospitalizations, specifically, can provide a better picture of the demographics, injuries, comorbid conditions, and costs for individuals who have experienced the most serious forms of IPV [25],[26]. Only a few studies have examined characteristics associated with IPV-related hospitalizations, possibly due to limitations of available data, including incomplete medical record data, misclassification of IPV as other forms of trauma or accidents (possibly as a result of patients not disclosing abuse), and underuse of IPV-specific billing codes, which may result in insufficient sample sizes that preclude generation of reliable estimates of hospitalizations involving IPV. Rudman and Davey [27] utilized 1994 Healthcare Cost and Utilization Project (HCUP) data to examine the incidence of hospitalizations related to IPV for the entire US and reported that non-white and younger individuals were more likely to be hospitalized for IPV and have primary diagnoses related to acute injuries from violence, chronic disease, and mental health issues. Kernic and colleagues found that women who experienced IPV had an increased relative risk of hospitalization for assault, mental health issues, digestive system diseases, injuries and poisonings, and suicide attempts [28]. Statewide surveillance of inpatient discharge data and single site medical record reviews have also contributed to our knowledge surrounding inpatient healthcare utilization patterns associated with IPV [29],[30]. One study of two Level I trauma centers in Kalamazoo County Michigan found IPV-exposed individuals were ten times more likely to be hospitalized for injuries compared to national age-matched controls, and over half of the cases involved drugs and alcohol [29].

Although these few studies have enhanced our understanding of IPV-related hospitalizations, very little is known about inpatient care provided to individuals exposed to IPV residing in rural areas and no information is currently available regarding healthcare utilization and costs associated with IPV in the highly rural Appalachian region, despite the presence of multiple vulnerabilities that increase the risk for experiencing severe forms of IPV and associated health consequences [5]. Current research in this area involves sample sizes too small to make inferences about the Appalachian region as a whole or utilizes state or national level data that precludes county-level analyses required for examining the entirety of Appalachia. Data from the Healthcare Cost and Utilization Project, managed by the Agency for Healthcare Research and Quality, provide an opportunity to examine county-level hospitalization events, and patterns of healthcare utilization and costs in Appalachia. The objective of this study was to compare county-level population rates of IPV-related hospitalizations across Appalachia and non-Appalachian US counties, and to differentiate sociodemographic and clinical characteristics of the hospitalizations between the geographic areas.

Methods

This study uses 2007–2011 data from the State Inpatient Databases, which are part of Healthcare Cost and Utilization Project. The Healthcare Cost and Utilization Project is a federal-state-industry partnership sponsored by the Agency for Healthcare Research and Quality that compiles and provides health data for healthcare policy and outcomes research [31]. The State Inpatient Databases’ files contain all inpatient records from community hospitals in each participating state. Collectively, these files contain clinical and non-clinical data on approximately 97% of all hospital discharges in the US. These data are standardized to permit multi-state and geographical comparisons [32]. IPV-related hospitalizations in Appalachian and Non-Appalachian counties were identified and extracted from the 2007–2011 intramural State Inpatient Databases’ files maintained by the Agency for Healthcare Research and Quality according to the methods detailed below. We received approval from the West Virginia University Institutional Review Board to carry out this study.

Results

Between 2007 and 2011, there were 7,385 IPV-related hospitalizations (2,645 Appalachian, 4,740 non-Appalachian). No statistically significant differences were found between the Appalachian and non-Appalachian counties with regard to sex, hospitalization admission day, length of stay, and in-hospital mortality (Table 1). Appalachian patients hospitalized for IPV were slightly older than those in non-Appalachian counties (53.4 years [range = 18–107] vs. 52.3 years [range = 18–104]; p = 0.04). Compared to the non-Appalachian region, individuals hospitalized in Appalachia were more likely to identify as White whereas hospitalized individuals in the non-Appalachian region were more likely to identify as Black or Hispanic. Almost two-thirds of patients hospitalized for IPV in Appalachia lived in communities with the lowest annual median income quartile (≤$38,999) compared with 35% of patients in non-Appalachian counties. Almost 15% of non-Appalachian IPV-related hospitalizations involved patients from neighborhoods in the wealthiest income quartile (>$64,000/year) versus 3% of Appalachian hospitalizations. A greater proportion of Appalachian patients utilized Medicare or Medicaid as their primary payer, while those in non-Appalachian counties were more likely to pay for their healthcare through private insurance.

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Table 1. Sociodemographic variables and hospitalization characteristics^a.

https://doi.org/10.1371/journal.pone.0184222.t001

Hospitalization rates

The IPV-related hospitalization rate was 14% higher in Appalachian counties compared to non-Appalachian counties (3.09 per 100,000 versus 2.71 per 100,000, respectively). After adjustment for age and rurality, Appalachian counties had a 22% higher rate of hospitalization related to IPV compared to non-Appalachian counties (RR: 1.22, 95% CI: 1.14–1.31) (Table 2).

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Table 2. IPV-related hospitalizations for Appalachia and non-Appalachian counties in the US, 2007–2011.

https://doi.org/10.1371/journal.pone.0184222.t002

The top 15 most frequent diagnoses and procedures associated with IPV-related hospitalizations stratified by Appalachian and non-Appalachian counties are found in Tables 3 and 4. Mood disorders were a top diagnosis in both groups, but were twice as prevalent in Appalachia (20.2% vs. 10.0%). Substance use disorders and poisonings, urinary tract infections and pregnancy-related issues were also observed in both Appalachian and non-Appalachian counties; however, intracranial and internal injuries were among the top 15 diagnoses in non-Appalachian counties, only. Alcohol and drug rehabilitation/detoxification was the most common primary procedure indicated in both Appalachian and non-Appalachian regions, but occurred at a higher frequency within Appalachia (16.5% vs. 7.2%). Intubation, ventilation and blood transfusions were also common procedures performed for patients admitted to the hospital for IPV. Pregnancy-related procedures (delivery assistance, Cesarean section, fetal monitoring), psychiatric and psychological evaluation/therapy and treatment for wounds and fractures were also reported for patients in both regions.

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Table 3. Top fifteen comorbid diagnoses for IPV-related hospitalizations in Appalachia and non-Appalachian counties in the US, 2007–2011.

https://doi.org/10.1371/journal.pone.0184222.t003

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Table 4. Top fifteen primary procedures for IPV-related hospitalizations in Appalachia and non-Appalachian counties in the US, 2007–2011.

https://doi.org/10.1371/journal.pone.0184222.t004

Discussion

Socioeconomically disadvantaged and rural communities are considered health disparity groups by the National Institutes of Health [36]. Some areas within the largely rural region of Appalachia face considerable disadvantage and disparities related to mental health, chronic disease, substance abuse and injury and available preventive services and treatment for these conditions [14–20]. The current study adds to the literature by providing new information about healthcare utilization and costs associated with IPV in Appalachia. To the best of our knowledge, this is the first study to examine IPV-related hospitalizations in Appalachia and make comparisons with non-Appalachian counties. To successfully complete this analysis, it was necessary to use the restricted, intramural State Inpatient Databases’ files at the Agency for Healthcare Research and Quality due to variable restrictions on the publicly available data files.

Our primary finding was that Appalachian counties had a significantly higher rate of IPV-related hospitalizations compared to a sample of non-Appalachian counties. The explanation for the difference between the two regions is likely multifactorial, though characteristics associated with rurality may partially account for the findings. While previous research has shown rates of IPV to be roughly equivalent in urban and rural areas [5], some studies have demonstrated individuals living in inner-city urban areas to be at increased risk for IPV and IPV-related health consequences [4],[37–40]. While Appalachia is twice as rural as the non-Appalachian US, over half of the region is comprised of suburban or urban areas. In the current study, the highest rates of IPV-related hospitalizations were found in rural Appalachian counties. Thus, it is plausible that rural areas within Appalachia are inherently different from the suburban and urban locales within the region (non-rural Appalachia) as well as other rural, non-Appalachian areas of the US. This highlights the importance of examining the urban-rural continuum regionally versus solely at state or national levels. Edwards’ recent critical review of the IPV literature found rural IPV to be more chronic and severe and result in worse physical and psychosocial health outcomes for individuals who have experienced violence [5], and Logan and colleagues found that perpetrators of IPV in rural areas are more likely to use knives or guns—injuries which may necessitate hospitalization [7]. Additionally, rural locales have fewer IPV services and IPV-exposed individuals in rural areas report less help seeking behaviors and more difficulty accessing medical care [5]. Further, compared with the rest of the US, Appalachian counties report higher aggregate healthcare costs and more disparities in access to care [41]. Thus, the higher IPV-related hospitalization rate in Appalachia might not be a function of a higher prevalence of IPV, but instead may reflect overutilization of emergency or inpatient services due to shortages in preventive and IPV-specific services in the medically underserved region. Because IPV frequency and severity increases over time, individuals without adequate means to address IPV might remain in situations of escalating abuse that eventually require emergent inpatient care. This disparity in access to resources may be especially pronounced among Appalachian residents living in the most rural, isolated areas.

In addition to rurality, sociodemographic differences between the two regions may explain Appalachia’s higher rate of IPV-related hospitalizations. Appalachian patients were older than their non-Appalachian counterparts, were more likely to identify as White, and have public versus private insurance. They were also more likely to reside in the poorest neighborhoods—only 3% of Appalachian patients hospitalized for IPV lived in communities with the highest income quartile of >$64,000 per year. These data are reflective of the Appalachian population as a whole: residents of Appalachia are more racially homogenous (83% White) than the total US population (63% White), significantly older (median age = 40 years vs. 37 years), and have a higher proportion of residents aged 65 years and older (16% vs 13%). Appalachians are also less likely to have at least a bachelor’s level of education (22% vs. 29%) and they have significantly lower incomes than non-Appalachian residents. Moreover, the households with the lowest incomes in Appalachia are found within the most rural counties [42]. In a recent study, Edwards et al [43] found that rural communities with high poverty and low collective efficacy (ie, social cohesion among community members and willingness to intervene for the common good) [44] experienced the highest rates of IPV. Low income levels in particular have been shown to be one of the strongest predictors of IPV, even after controlling for race/ethnicity [45]. In addition, while many studies have found racial/ethnic minority populations disproportionately experience IPV [40],[46–48] and are more likely to be hospitalized as a result [28], less is known about IPV risk and outcomes among White populations living in poor, predominately White communities [49]. While large amounts of missing data on race/ethnicity within the State Inpatient Databases precluded our ability to reliably control for race/ethnicity in our regression analyses, examining IPV risk, healthcare utilization patterns, and health and psychosocial outcomes across racial/ethnic groups in Appalachia is an important next step for future research.

While it is not surprising that Appalachian patients were slightly older than non-Appalachian counterparts, the older age of patients in both regions contrasts with other studies that have found younger (≤30) populations are at increased risk for IPV-related hospitalizations [27]. However, Shafer et al reported that although most patients exposed to IPV who sought emergency department services were between ages 20–29, those 50 years or older were more frequently hospitalized [30]. This suggests that, while younger groups may be at increased risk for IPV, older patients who have experienced IPV may be more likely to be hospitalized due to comorbidities and other chronic conditions (eg, osteoporosis that contributes to more severe fractures, anticoagulants that contribute to more extensive bleeding).

The top diagnoses shown in Table 3 mirror what has been reported in other studies of IPV-related hospitalizations, wherein mental disorders, suicide attempts, traumatic injuries and assault, drug addiction and poisonings, and pregnancy complications were listed as top diagnoses among hospitalized patients [27],[28],[30]. There were notable differences in comorbid diagnoses and procedures between Appalachian and non-Appalachian patients, however. Comorbidities related to substance use and mental health issues were more frequently observed among Appalachian patients while non-Appalachian patients had more diagnoses and procedures indicative of acute IPV-related injuries (eg, intracranial, crushing, and internal injuries, sutures, CT scans). The high prevalence of comorbid diagnoses and procedures related to both mental health and substance use disorders among Appalachian patients with hospitalizations related to IPV is noteworthy, but not unexpected, as the co-occurrence of IPV, mental health issues and substance use is well-established [24],[50–53]. Likewise, Appalachia faces significant disparities related to mental health and substance use disorders, including epidemic rates of prescription opioid and heroin use. Using state, sub-state, and county level data from 2000 to 2005, Zhang found that Appalachian adults have a higher prevalence of mental health disorders compared to the rest of the nation, specifically with regard to psychological distress and major depressive disorder and that use rates of tobacco, prescription opiates, and psychotherapeutics (ie, pain relievers, tranquilizers, stimulants, sedatives) are higher in Appalachia compared with the US, especially in coal mining communities [17]. Furthermore, while Appalachians are admitted to treatment for the use of opiates and synthetic drugs at a higher rate than in other regions of the US, there are fewer substance abuse treatment facilities that offer outpatient detoxification in Appalachia when compared to facilities outside of the region and more patients in Appalachia are admitted to community hospitals for mental health or substance abuse treatment via the emergency department, especially in coal mining areas and counties with the greatest economic distress [17]. Together, these data may explain why, in the current study, ‘Alcohol and drug rehabilitation/detoxification’ was the top procedure code listed among patients with IPV-related hospitalizations in both regions, but was observed much more frequently in Appalachian counties.

Urinary tract infections and pregnancy-related issues were prevalent in Appalachian and non-Appalachian groups. Previous research has found women experiencing IPV are more likely to be diagnosed with urinary tract infections [54],[55] and pregnancy may increase IPV risk [56],[57], especially among women with lower socioeconomic status [58]. Lipsky and colleagues found women reporting IPV exposure were more likely to be hospitalized during pregnancy with diagnoses related to injuries, violence, pregnancy complications, substance abuse and mental health issues [59].

Conclusions

Hospitalizations for IPV were disproportionately higher in Appalachian counties in the US, suggesting a possible health disparity issue. Exploring potential disparities in healthcare utilization and costs associated with IPV in the Appalachian region is critical for the development of future interventions and prevention programs to effectively target the needs of this population. Other public health problems that disproportionately affect Appalachian communities (eg, cancer, obesity, prescription opioid abuse) have received federal and local attention and increased funding. Funding is needed for future research to examine the unique contextual factors that contribute to IPV in Appalachian communities, and the potential relationship between IPV and other health disparities in the region.

Supporting information

Acknowledgments

We would like to sincerely thank Rick Jordan at the Agency for Healthcare Research and Quality for his invaluable assistance with SAS programming and database support. The authors would also like to thank the State data organizations that participated in the Healthcare Cost and Utilization Project (HCUP) contributing data used in this study: Alaska State Hospital and Nursing Home Association; Arizona Department of Health Services; Arkansas Department of Health; California Office of Statewide Health Planning and Development; Colorado Hospital Association; Connecticut Hospital Association; District of Columbia Hospital Association; Florida Agency for Health Care Administration; Georgia Hospital Association; Hawaii Health Information; Corporation; Illinois Department of Public Health; Indiana Hospital Association; Iowa Hospital Association; Kansas Hospital Association; Kentucky Cabinet for Health and Family Services; Louisiana Department of Health and Hospitals; Maine Health Data Organization; Maryland Health Services Cost Review Commission; Massachusetts Center for Health Information and Analysis; Michigan Health & Hospital Association; Minnesota Hospital Association (provides data for Minnesota and North Dakota hospitals); Mississippi Department of Health; Missouri Hospital Industry Data Institute; Montana MHA—An Association of Montana Health Care Providers; Nebraska Hospital Association; Nevada Department of Health and Human Services; New Hampshire Department of Health & Human Services; New Jersey Department of Health; New Mexico Department of Health; New York State Department of Health; North Carolina Department of Health and Human Services; North Dakota (data provided by the Minnesota Hospital Association); Ohio Hospital Association; Oklahoma State Department of Health; Oregon Office of Health Analytics; Oregon Association of Hospitals and Health Systems; Pennsylvania Health Care Cost Containment Council; Rhode Island Department of Health; South Carolina Revenue and Fiscal Affairs Office; South Dakota Association of Healthcare; organizations; Tennessee Hospital Association; Texas Department of State Health Services; Utah Department of Health; Vermont Association of Hospitals and Health Systems; Virginia Health Information; Washington State Department of Health; West Virginia Health Care Authority; Wisconsin Department of Health Services; Wyoming Hospital Association.