Risk factors for assaultive reinjury and death following a nonfatal firearm assault injury: A population-based retrospective cohort study

Machine learning classification of new firearm injury encounters in the St Louis region: 2010-2020

OBJECTIVES

To improve firearm injury encounter classification (new vs follow-up) using machine learning (ML) and compare our ML model to other common approaches.

MATERIALS AND METHODS

This retrospective study used data from the St Louis region-wide hospital-based violence intervention program data repository (2010-2020). We randomly selected 500 patients with a firearm injury diagnosis for inclusion, with 808 total firearm injury encounters split (70/30) for training and testing. We trained a least absolute shrinkage and selection operator (LASSO) regression model with the following predictors: admission type, time between firearm injury visits, number of prior firearm injury emergency department (ED) visits, encounter type (ED or other), and diagnostic codes. Our gold standard for new firearm injury encounter classification was manual chart review. We then used our test data to compare the performance of our ML model to other commonly used approaches (proxy measures of ED visits and time between firearm injury encounters, and diagnostic code encounter type designation [initial vs subsequent or sequela]). Performance metrics included area under the curve (AUC), sensitivity, and specificity with 95% confidence intervals (CIs).

RESULTS

The ML model had excellent discrimination (0.92, 0.88-0.96) with high sensitivity (0.95, 0.90-0.98) and specificity (0.89, 0.81-0.95). AUC was significantly higher than time-based outcomes, sensitivity was slightly (but not significantly) lower than other approaches, and specificity was higher than all other methods.

DISCUSSION

ML successfully delineated new firearm injury encounters, outperforming other approaches in ruling out encounters for follow-up.

CONCLUSION

ML can be used to identify new firearm injury encounters and may be particularly useful in studies assessing re-injuries.

Risk and Protective Factors for Firearm Assault Injuries Among Black Men: A Scoping Review of Research

Black men are disproportionately affected by firearm assaults in the United States, and these disparities are rooted in structural and social inequities. The objective of this scoping review of research was to identify risk and protective factors for firearm assault injuries among Black men at all levels of the social-ecological framework. The search was conducted in 2021. The initial search generated 1,122 articles. Studies were eligible if they (a) included an analysis of modifiable risk or protective factors for firearm assaults among Black men; (b) reported an estimate of correlation, association, or effect between risk or protective factors and firearm assault injuries, firearm violence, and/or firearm homicides; and (c) were published peer-reviewed articles. In all, 19 articles were identified for review. Risk factors identified at each ecological level include the following: (1) Individual: firearm possession/weapon use and criminal legal system interaction; (2) Relationships: gang membership and exposure to other people who have experienced a firearm assault; (3) Community: indicators for socioeconomic status and racial residential segregation; and (4) Societal: historical racist policy. Individual-level substance use had mixed results. Few (26%) studies examined protective factors at any ecological level, but community-level factors like neighborhood tree cover were identified. Future research needs to examine risk and protective factors at the societal level and multiple ecological levels simultaneously leading to more effective multi-level interventions that will guide policy formation. A greater diversity of study designs, research methods, and theoretical frameworks is needed to better understand factors associated with firearm assault among Black men.

Health Care Utilization After Nonfatal Firearm Injuries

OBJECTIVES

Despite the high incidence of firearm injuries, little is known about health care utilization after nonfatal childhood firearm injuries. This study aimed to describe health care utilization and costs after a nonfatal firearm injury among Medicaid and commercially insured youth using a propensity score matched analysis.

METHODS

We conducted a propensity score matched cohort analysis using 2015 to 2018 Medicaid and Commercial Marketscan data comparing utilization in the 12-months post firearm injury for youth aged 0 to 17. We matched youth with a nonfatal firearm injury 1:1 to comparison noninjured youth on demographic and preindex variables. Outcomes included inpatient hospitalizations, emergency department (ED) visits, and outpatient visits as well as health care costs. Following propensity score matching, regression models estimated relative risks of the health care utilization outcomes, adjusting for demographic and clinical covariates.

RESULTS

We identified 2110 youth with nonfatal firearm injury. Compared with matched noninjured youth, firearm injured youth had a 5.31-fold increased risk of inpatient hospitalization (95% confidence interval [CI] 3.93-7.20), 1.49-fold increased risk of ED visit (95% CI 1.37-1.62), and 1.06-fold increased risk of outpatient visit (95% CI 1.03-1.10) 12-months postinjury. Adjusted 12-month postindex costs were $7581 (95% CI $7581-$8092) for injured youth compared with $1990 (95% CI $1862-2127) for comparison noninjured youth.

CONCLUSIONS

Youth who suffer nonfatal firearm injury have a significantly increased risk of hospitalizations, ED visits, outpatient visits, and costs in the 12 months after injury when compared with matched youth. Applied to the 11 258 US youth with nonfatal firearm injuries in 2020, estimates represent potential population health care savings of $62.9 million.

Incidence of and Factors Associated With Recurrent Firearm Injury Among Patients Presenting to St. Louis Trauma Centers, 2010 to 2019 : A Cohort Study

BACKGROUND

Firearm injuries are a public health crisis in the United States.

OBJECTIVE

To examine the incidence and factors associated with recurrent firearm injuries and death among patients presenting with an acute (index), nonfatal firearm injury.

DESIGN

Multicenter, observational, cohort study.

SETTING

Four adult and pediatric level I trauma hospitals in St. Louis, Missouri, 2010 to 2019.

PARTICIPANTS

Consecutive adult and pediatric patients (n = 9553) presenting to a participating hospital with a nonfatal acute firearm injury.

MEASUREMENTS

Data on firearm-injured patient demographics, hospital and diagnostic information, health insurance status, and death were collected from the St. Louis Region-Wide Hospital-Based Violence Intervention Program Data Repository. The Centers for Disease Control and Prevention (CDC) Social Vulnerability Index was used to characterize the social vulnerability of the census tracts of patients' residences. Analysis included descriptive statistics and time-to-event analyses estimating the probability of experiencing a recurrent firearm injury.

RESULTS

We identified 10 293 acutely firearm-injured patients of whom 9553 survived the injury and comprised the analytic sample. Over a median follow-up of 3.5 years (IQR, 1.5 to 6.4 years), 1155 patients experienced a recurrent firearm injury including 5 firearm suicides and 149 fatal firearm injuries. Persons experiencing recurrent firearm injury were young (25.3 ± 9.5 years), predominantly male (93%), Black (96%), and uninsured (50%), and resided in high social vulnerability regions (65%). The estimated risk for firearm reinjury was 7% at 1 year and 17% at 8 years.

LIMITATIONS

Limited data on comorbidities and patient-level social determinants of health. Inability to account for recurrent injuries presenting to nonstudy hospitals.

CONCLUSION

Recurrent injury and death are frequent among survivors of firearm injury, particularly among patients from socially vulnerable areas. Our findings highlight the need for interventions to prevent recurrence.

PRIMARY FUNDING SOURCE

Emergency Medicine Foundation-AFFIRM and Missouri Foundation for Health.

Firearm injury prevention counseling for patients with traumatic brain injury: a survey of brain injury physicians

Background

Survivors of traumatic brain injury are at increased risk for firearm-related injuries, including suicide.

Aims

To determine current practices of Brain Injury Medicine (BIM) physicians and their rehabilitation teams in assessing patients' access to firearms and in providing firearm safety education, and the impact of having received training on this topic on physicians' likelihood of inquiring about patients' access to firearms.

Methods

14-item web-based cross-sectional survey of 86 U.S. physiatrists board-certified in BIM.

Results

81% of respondents indicated they believe BIM physicians should counsel their patients on firearm safety but only 12.9% reported always doing so. Fifteen percent reported always inquiring about their patients' access to firearms. 88.2% indicated having never received formal training on firearm injury prevention counseling. Physicians who received such training had 7.5 times higher odds of reporting at least sometimes inquiring about patients' access to firearms than those who were not trained [95% confidence interval (1.94, 28.64)]. They also had 5.7 times higher odds for reporting being at least moderately comfortable providing patients firearm safety counseling [95% CI: (1.39, 23.22)].

Conclusion

While most BIM specialists who responded to this survey believe they should counsel patients on firearm safety, few always or usually do so. Moreover, most do not routinely inquire about their patients' access to firearms. The provision of firearm injury prevention training to BIM physicians was strongly associated with an increased likelihood they will inquire about their patients' access to guns and with an improved comfort level in providing counseling on this subject matter.

A systematic review of recurrent firearm injury rates in the United States

OBJECTIVES

To conduct a systematic review of methodologies, data sources, and best practices for identifying, calculating, and reporting recurrent firearm injury rates in the United States.

METHODS

In accordance with PRISMA guidelines, we searched seven electronic databases on December 16, 2021, for peer-reviewed articles that calculated recurrent firearm injury in generalizable populations. Two reviewers independently assessed the risk of bias, screened the studies, extracted data, and a third resolved conflicts.

FINDINGS

Of the 918 unique articles identified, 14 met our inclusion criteria and reported recurrent firearm injury rates from 1% to 9.5%. We observed heterogeneity in study methodologies, including data sources utilized, identification of subsequent injury, follow-up times, and the types of firearm injuries studied. Data sources ranged from single-site hospital medical records to comprehensive statewide records comprising medical, law enforcement, and social security death index data. Some studies applied machine learning to electronic health records to differentiate subsequent new firearm injuries from the index injury, while others classified all repeat firearm-related hospital admissions after variably defined cut-off times as a new injury. Some studies required a minimum follow-up observation period after the index injury while others did not. Four studies conducted survival analyses, albeit using different methodologies.

CONCLUSIONS

Variability in both the data sources and methods used to evaluate and report recurrent firearm injury limits individual study generalizability of individual and societal factors that influence recurrent firearm injury. Our systematic review highlights the need for development, dissemination, and implementation of standard practices for calculating and reporting recurrent firearm injury.

Development of a clinical prediction instrument to estimate risk of initial violent injury

BACKGROUND

Interpersonal violent injury is a public health crisis, disproportionately affecting young people of color. We aimed to evaluate associations between sociobehavioral predictors and first-time violent injury, and to develop a predictive risk score for violent injury.

METHODS

We performed a retrospective case-cohort study of adolescents aged 12-18 years. Multivariable logistic regression was used to estimate associations between 35 candidate variables and interpersonal first-time violent injury resulting in an emergency department (ED) visit. Multiple imputation was used to account for missing values and a risk score was developed by multiplying regression coefficients by 10 to generate a composite tool to predict initial violent injury (IVI). Discrimination and calibration were assessed using 10-fold cross validation.

RESULTS

19,210 adolescents were included, 276 (1.4%) as victims of IVI. The final model, the Initial Violent Injury Risk Prediction Tool (IVI-RPT), included: age, fight within the prior year, trouble with the law, and alcohol use. IVI-RPT scores were categorized as: 0-7 (low risk), 8-16 (moderate), and 17-26 (high), and IVI prevalence was 0.8% (95% confidence interval [CI]: 0.6%, 0.9%), 2.5% (95% CI: 1.9%, 3.1%), and 5.3% (95% CI: 4.1%, 6.6%), respectively. The area under the receiver operating characteristic curve was 0.70 (95% CI: 0.66, 0.73), while the slope of the calibration curve was 1.1 (95% CI: 0.9, 1.2).

CONCLUSIONS

We developed a promising clinical prediction instrument, the IVI-RPT, that categorizes individuals into risk groups with increasing probabilities of violent injury. External validation of this tool is required prior to clinical practice implementation.

Linking out-of-hospital deaths with a regional hospital-based firearm injury database: a clinical researcher's guide to accessing data from the National Death Index

IntroductionFirearm injuries are a public health crisis in the US. The National Death Index (NDI) is a well-established, comprehensive database managed by the National Center for Health Statistics at the CDC. In this methodology paper we describe our experience accessing and linking data from the NDI to our regional, hospital-based violent injury database to identify out-of-hospital deaths from firearms.

METHODS

We outline the key steps of our submission to the NDI. Data were collected from research team meeting notes, team member emails with NDI staff, and information provided from the NDI website and supplementary guides. Few of our collaborators or university partner investigators had accessed or used data from the NDI. We discuss the online NDI Processing Portal data request, data preparation and receipt from the NDI, troubleshooting tips, and a timeline of events.

RESULTS

Our query to the NDI returned 12 034 records of 12 219 firearm-injured patient records from 2010 and 2019. The record match rate was 98.5%.

DISCUSSION

Linking hospital-based data sets with NDI data can provide valuable information on out-of-hospital deaths. This has the potential to improve the quality of longitudinal morbidity and mortality calculations in hospital-based patient cohorts. We encountered logistic and administrative challenges in completing the online NDI Processing Portal and in preparing and receiving data from the NDI. It is our hope that the lessons learnt presented herein will help facilitate easy and streamlined acquisition of valuable NDI data for other clinical researchers.

WHAT THIS STUDY ADDS

- A step-by-step guide for clinical researchers of how to apply to access data from the National Death Index (NDI).- Advice and lessons learned on how to efficiently and effectively access data from the NDI.- A well-described methodology to improve the quality of longitudinal morbdity and mortality calculations in hospital-based cohorts of firearm injured patients.What is already known on this subject:- There is a need for robust, longitudinal data sources that reliably track morbidity and mortality among firearm injured patients in the United States.- The NDI is a well-established, comprehensive database that holds death records for all 50 states, which provides valuable mortality data to the public health and medical research community.

The association between food insecurity and gun violence in a major metropolitan city

BACKGROUND

Food insecurity (FI) is an important social determinant of health that is associated with many forms of violence. We hypothesized that FI would be associated with gun violence.

METHODS

Firearm injury data was collected from 2016 to 2020 (n = 3115) at a single institution that serves as the only Level I trauma center in a major southern US city. The data were linked with Map the Meal Gap data, a publicly available data set, which estimates rates of county-level FI based on state-level FI and social determinants, including unemployment, poverty, disability, and other factors. Regression analysis was utilized to examine the relationship between FI with rates of overall gun trauma and odds of gun-related violence. Food insecurity by county of patient residence was categorized by rates less than the national average of 11.5% (low), between the national and state average (16.5%) (moderate), and greater than the state average (high). Out of state residents were excluded from the analyses.

RESULTS

Of the 3,115 patients with firearm injuries identified, 138 (4.4%) resided in counties with low FI rates, 1048 (33.6%) in moderate FI, and 1929 (62.0%) in counties with high FI. Patients in regions of high FI were more likely to be a Level I trauma activation, a victim of assault, and have Medicaid or be self-pay. There was no significant difference in mortality by levels of FI. Food insecurity was significantly associated with firearm injury, with each percent increase in FI being related to approximately 56 additional gun-related injuries per 100,000 people (95% confidence interval, 54-59) and increased odds of the injury classified as assault (odds ratio, 1.13; 95% confidence interval, 1.07-1.19).

CONCLUSION

Violence prevention initiatives targeting food insecure communities may help alleviate the US gun violence epidemic. Further, trauma center screening for household FI and in-hospital interventions addressing FI may help reduce gun violence recidivism.

LEVEL OF EVIDENCE

Prognostic and Epidemiologic; Level IV.

Talking about firearm injury prevention with patients: a survey of medical residents

BACKGROUND

Firearm injury and death are significant public health problems in the U.S. and physicians are uniquely situated to help prevent them. However, there is little formal training in medical education on identifying risk for firearm injury and discussing safe firearm practices with patients. This study assesses prior education, barriers to counseling, and needs for improved training on firearm safety counseling in medical education to inform the development of future education on clinical strategies for firearm injury prevention.

METHOD

A 2018 survey administered to 218 residents and fellows at a large, academic medical center asked about medical training on firearm injury prevention, frequency of asking patients about firearm access, and perceived barriers.

RESULTS

The most common barriers cited were not knowing what to do with patients' answers about access to firearms (72.1%), not having enough time (66.2%), not feeling comfortable identifying patients at-risk for firearm injury (49.2%), and not knowing how to ask patients about firearm access (48.6%). Prior education on firearm injury prevention was more strongly associated with asking than was personal exposure to firearms: 51.5% of respondents who had prior medical education reported asking compared with who had not received such education (31.8%, p=0.004). More than 90% of respondents were interested in further education about interventions, what questions to ask, and legal mechanisms to separate dangerous people from their firearms.

CONCLUSIONS

Education on assessing risk for firearm-related harm and, when indicated, counseling on safe firearm practices may increase the likelihood clinicians practice this behavior, though additional barriers exist.

Incidence, Distribution, and Lethality of Firearm Injuries in California From 2005 to 2015

IMPORTANCE

Little is known about nonfatal firearm injuries in the United States, and national estimates based on emergency department samples may not be accurate.

OBJECTIVE

To describe the incidence and distribution of nonfatal firearm injuries and estimate case fatality ratios (CFRs) for firearm injuries by external cause of injury code within California overall and by race/ethnicity, including an assessment of trends over time and geographic variation within the state.

DESIGN, SETTING, AND PARTICIPANTS

This serial cross-sectional study used complete statewide data for firearm-related mortality, emergency department visits, and hospitalizations among California residents from January 1, 2005, through December 31, 2015, to analyze incidence, distribution, and CFRs of firearm injury. Data were analyzed from 2018 to 2019.

EXPOSURES

All individuals in California with a firearm injury based on International Classification of Diseases, Ninth Revision or International Statistical Classification of Diseases and Related Health Problems, Tenth Revision codes were included.

MAIN OUTCOMES AND MEASURES

Counts and rates of nonfatal firearm injuries overall and stratified by external cause, sex, and race/ethnicity; total and clinical CFRs. Clinical CFR was calculated based on individuals treated in emergency departments or hospitals.

RESULTS

Over the study period, there were 81 085 firearm-related emergency department visits and hospitalizations among individuals with a mean (SD) age of 27.5 (11.9) years, 72 567 (89.6%) of whom were men. Nonfatal firearm injuries in California decreased by 38.1% between 2005 and 2015, driven by a 46.4% decrease in assaultive injuries. Self-inflicted injuries and unintentional injuries remained relatively stable. The overall CFR for firearm injuries increased from 27.6% in 2005 to 32.2% in 2015 for a relative increase of 20.7%, while the clinical CFR remained stable between 7.0% and 9.0%.

CONCLUSIONS AND RELEVANCE

These findings suggest that although the number of firearm injuries has decreased in California, the lethality of these injuries has not. Similar studies from other states could provide more information about these trends nationwide.