Firearm-related morbidity and mortality by injury intent: Analysis of medical, criminal, and vital records in Seattle, WA

BACKGROUND

Due to the reliance on administrative records in firearm injury research, individual studies do not present an integrated picture of firearm injuries. Non-fatal and fatal injuries are frequently studied separately, as are injuries of different intents. Certain risk factors for assault-related firearm injuries, like characteristics of the neighborhoods where they occur, the injured person’s involvement with criminal activity, or their mental health may also indicate an increased risk of self-inflicted, unintentional, or legal intervention firearm injury. However, identifying differences or similarities between intent-specific firearm injury groups requires the inclusion of all intent-specific firearm injuries, fatal and non-fatal, in a single study, using all available data, to present a more integrated picture of firearm injury. Clarifying the specific associations between firearm injury risk factors and assault-related, self-inflicted, unintentional, and legal intervention firearm injuries can inform targeted interventions.

METHODS

This study clarifies risk markers for intent-specific firearm injury both at the neighborhood level and the individual level. To examine relations between neighborhood-level characteristics and rate/density of intent-specific firearm injury, we conducted an ecological study of firearm injuries in Seattle from 2005-2014, geocoded by residence (for injury rates) and occurrence locations (for injury densities). Using the Seattle Neighborhoods and Crime Survey, counts of intent-specific firearm injuries per census tract were modeled as a function of “code of the streets,” fear of crime, handgun ownership, and negative opinions of police, adjusted for neighborhood disadvantage. To examine relations between arrest history and risk of intent-specific firearm injury, we used a case-control study to compare 10-year arrest histories of individuals with intent-specific firearm injuries to a control group of motor vehicle passengers with unintentional injuries in Seattle. All initial injuries occurring 2005-2014 among adults (21+ years) were included. To examine relations between arrest, substance use disorder, and mental disorder histories and risk of intent-specific firearm injury we used a case-control study to compare two-year diagnosis and arrest histories of intent-specific firearm injury patients (cases) to unintentionally injured motor vehicle collision (MVC) passengers (controls). We included all initial fatal and non-fatal firearm and MVC injuries occurring 2010-2014 in Seattle or to Seattle residents, limited to individuals ages 13+. For both case-control studies hospital and death records were probabilistically linked to statewide arrest and (for the second case-control study) hospitalization records. Multinomial logistic regression was used to compare odds of each arrest or diagnosis-related exposure among intent-specific firearm injury cases relative to controls, adjusting for age, race, and gender.

RESULTS

Based on 1368 firearm injuries occurring in Seattle 2005-2014, we found specific neighborhood characteristics were associated with the rate/density of different intent-specific firearm injury categories, including associations with neighborhood scores on “code of the streets,” fear of crime, handgun ownership, and negative opinions of the police. In examining the 10-year arrest history of 1211 adult firearm injury cases and 522 controls, we found individuals with assault-related or legal intervention firearm injuries were more likely than controls to have been arrested for a variety of crimes, including drug-related felonies and violent crimes. Individuals with self-inflicted firearm injury were less likely than controls to have a history of felony arrests but were more likely to have an arrest history involving firearms. We found no significant differences in 10-year arrest history between individuals with unintentional firearm injury and controls. In examining the 2-year arrest, substance use disorder, and mental disorder diagnoses of 763 firearm injury cases and 335 controls ages 13+, we found no significant differences between unintentional and self-inflicted firearm injury cases and controls. Assault-related firearm injury cases were more likely than controls to have a prior felony record, regardless of prior substance use or mental disorder diagnoses. Legal intervention firearm injury cases were more likely than controls to have had a prior felony arrest as well as a diagnosis involving alcohol use, cannabis use, depression, psychosis, or conduct disorder.

CONCLUSIONS

Intent-specific firearm injuries display distinct patterns of association with neighborhood characteristics as well as individual-level arrest, substance use disorder, and mental disorder histories. Associations with neighborhood characteristics vary when examining place of occurrence versus place of residence, suggesting place-based interventions should consider place of residence and place of occurrence separately. Subjects with different intent-specific firearm injuries have distinct patterns of prior substance use, mental disorder, and arrest. Many of these injuries occurred after a series of prior encounters with law enforcement and medical professionals, suggesting these prior encounters are underutilized settings for firearm injury prevention programs.