Development of the SaFETy score: A clinical screening tool for predicting future firearm violence risk

Background: Interpersonal firearm violence among youth is a substantial public health problem, and emergency department (ED) physicians require a clinical screening tool to identify highrisk youth. Objective: To derive a clinically feasible risk index for firearm violence. Design: 24-month prospective cohort study. Setting: Urban, level 1 ED. Participants: Substance-using youths, aged 14 to 24 years, seeking ED care for an assault-related injury and a proportionately sampled group of non-assault-injured youth enrolled from September 2009 through December 2011. Measurements: Firearm violence (victimization/perpetration) and validated questionnaire items. Results: A total of 599 youths were enrolled, and presence/absence of future firearm violence during follow-up could be ascertained in 483 (52.2% were positive). The sample was randomly split into training (75%) and post-score-construction validation (25%) sets. Using elastic-net penalized logistic regression, 118 baseline predictors were jointly analyzed; the most predictive variables fell predominantly into 4 domains: violence victimization, community exposure, peer influences, and fighting. By selection of 1 item from each domain, the 10-point SaFETy (Serious fighting, Friend weapon carrying, community Environment, and firearm Threats) score was derived. SaFETy was associated with firearm violence in the validation set (odds ratio [OR], 1.47 [95% CI, 1.23 to 1.79]); this association remained (OR, 1.44 [CI, 1.20 to 1.76]) after adjustment for reason for ED visit. In 5 risk strata observed in the training data, firearm violence rates in the validation set were 18.2% (2 of 11), 40.0% (18 of 45), 55.8% (24 of 43), 81.3% (13 of 16), and 100.0% (6 of 6), respectively. Limitations: The study was conducted in a single ED and involved substance-using youths. SaFETy was not externally validated. Conclusion: The SaFETy score is a 4-item score based on clinically feasible questionnaire items and is associated with firearm violence. Although broader validation is required, SaFETy shows potential to guide resource allocation for prevention of firearm violence.