Firearm mortality and firearm injury hospitalisation in Florida after implementation of an extreme risk protection order law: a quasi-experimental study

Background Firearm-related injury is a leading cause of death in the USA. In 2018, Florida enacted an extreme risk protection order (ERPO) law authorising temporary firearm removal from individuals judged at high risk of violence or self-harm. We evaluated whether ERPO implementation was associated with changes in population firearm-related mortality and hospitalisation rates. Methods We conducted two population-level quasi-experimental analyses using CDC WONDER mortality data and the Florida State Inpatient Database. For mortality, Florida was compared with 21 non-ERPO states. For hospitalisations, quarterly firearm injury admissions were compared with a comparator outcome series using interrupted time-series analysis. The primary comparator was unintentional falls. Results Firearm-related death rates increased in Florida following ERPO implementation but rose less than projected by synthetic Florida (a weighted comparison of non-ERPO states estimating Florida’s mortality without the law); differences were not statistically significant for all firearm deaths (RR=0.94), firearm-related homicide (RR=0.86) or firearm-related suicide (RR=0.95). For hospitalisations, no statistically significant changes were observed relative to unintentional falls. There was no evidence of an immediate change in hospitalisation rates in the first quarter after the transition year (+0.46 per 100 000; 95% CI −0.06 to +0.97; p=0.08) and no change in trend over time (+0.06 per 100 000; 95% CI −0.04 to +0.16; p=0.23). Discussion ERPO implementation in Florida was not associated with detectable population-level changes in firearm mortality or hospitalisation trajectories. Given the targeted nature and relatively low uptake of ERPOs, population-level analyses may be underpowered to detect modest effects.