摘要：Objectives. We estimated the frequency and examined the characteristics of intimate partner homicide and related deaths in 16 US states participating in the National Violent Death Reporting System (NVDRS), a state-based surveillance system. Methods. We used a combination of quantitative and qualitative methods to analyze NVDRS data from 2003 to 2009. We selected deaths linked to intimate partner violence for analysis. Results. Our sample comprised 4470 persons who died in the course of 3350 intimate partner violence–related homicide incidents. Intimate partners and corollary victims represented 80% and 20% of homicide victims, respectively. Corollary homicide victims included family members, new intimate partners, friends, acquaintances, police officers, and strangers. Conclusions. Our findings, from the first multiple-state study of intimate partner homicide and corollary homicides, demonstrate that the burden of intimate partner violence extends beyond the couple involved. Systems (e.g., criminal justice, medical care, and shelters) whose representatives routinely interact with victims of intimate partner violence can help assess the potential for lethal danger, which may prevent intimate partner and corollary victims from harm. Intimate partner violence (IPV) is a serious public health problem that affects millions in the United States. IPV is defined as physical violence, sexual violence, stalking, or psychological aggression (including coercive tactics) by a current or former intimate partner. 1 IPV that is severe enough to lead to injury or significant harm is primarily but not always perpetrated by men. Estimates from the 2010 National Intimate Partner and Sexual Violence Survey indicate that more than 74 million people in the United States have experienced IPV (physical violence, sexual violence, stalking) at some point in their lives, and more than 12 million in the previous 12 months. 2 In the United States, IPV disproportionately affects women, especially racial/ethnic minorities. 2,3 The most extreme form of IPV is intimate partner homicide (IPH). In 2007, intimate partners committed 14% of all US homicides, and 70% of those victims were female. 4 Although IPH has decreased during the past 15 to 20 years, 4 it remains a disturbing possibility for people experiencing abusive relationships. Across studies, major risk factors for IPH consistently include previous domestic violence, unemployment, access to firearms, estrangement, threats to kill, threats with a weapon, previous nonfatal strangulation, a stepchild in the home (if the victim is female), and previous mental health problems of the perpetrator (for homicide–suicide). 5,6 Of these, previous IPV is the strongest predictor. 6 Furthermore, homicides followed by suicide of the perpetrator are more than twice as likely to be committed by former or current spouses as by other perpetrators and are significantly more likely to involve firearms than other weapons. 6,7 It is estimated that one third of IPHs in the United States involve suicide of the perpetrator, who is most often male. 6,8 The Centers for Disease Control and Prevention estimates that societal costs resulting from IPV victimization approach $6 billion annually. 9 Such cost estimates and scientific studies of IPH have largely focused on intimate partners of the perpetrator (e.g., spousal homicides). However, a substantial portion of IPV-related homicide victims are not the intimate partners themselves. These corollary victims may be family members, friends, neighbors, persons who intervene in IPV, law enforcement responders, or bystanders. Previous studies 10,11 have used the term “collateral victims” to refer to non–intimate partner victims in situations stemming from IPV. Because of the colloquial usage of “collateral” and out of concern for the negative connotations associated with the word, we selected the word “corollary” to refer to non–intimate partner victims whose death is connected to IPV. Few studies have examined corollary victims or included them in analyses of IPH. 10,11 In one exception, a British study examined murder connected to intimate partner conflict and found that 37% of the 166 victims were not intimate partners of the murderer. 10 Instead, the victims were children of the intimate partner, allies (e.g., relatives, neighbors, friends, lawyers connected to the abuse victim), or new partners. In the United States, it is difficult to estimate the magnitude of corollary victimization. Existing data systems, such as the Uniform Crime Reports, often use categories that do not provide the details necessary to understand the relationships among the victims and offenders. 12 For example, if an ex-husband kills his ex-wife’s new partner, the new partner may be categorized as an acquaintance. Furthermore, same-sex intimate partners are categorized as acquaintances in lieu of a more specific designation (e.g., romantic partner, domestic partner). At state and local levels, investigations conducted by fatality review boards may reveal the proportion of collateral victims resulting from IPV, but those figures are often not widely reported. We examined IPH data gathered between 2003 and 2009 by the National Violent Death Reporting System (NVDRS), a state-based surveillance system. Our objective was to extend the existing literature on the frequency and characteristics of IPH and on corollary homicides that occur in the context of IPV and IPH.
