Objective We aim to calculate the 5-year mortality after surviving to hospital discharge after a firearm injury and estimate the association of firearm injury with later mortality.

Methods We performed a retrospective cohort study of patients from an urban emergency department (ED) and trauma centre in Oakland, California, USA, in 2007. We created three cohorts of patients presenting for (1) gunshot wound (GSW), (2) MVC and (3) assault without a firearm. Demographic and clinical information was obtained from the clinical chart, and the California Department of Public Health Vital Statistics and Social Security Death Master File (2007–2012) were queried to identify patients who died.

Results We analysed 516 GSW patients, 992 MVC patients and 695 non-GSW assault patients. Of the GSW patients, 86.4% were alive at 5 years. All-cause 5-year mortality among GSW victims surviving to discharge after injury was 5.1%. Compared with MVC patients, both GSW and non-GSW assault patients have higher risk of death at 5 years (HR 2.54 (95% CI 1.41 to 4.59) and HR 1.64 (95% CI 1.01 to 2.68), respectively), adjusting for age, sex and race. Risk of death was higher in the first year for the GSW cohort (HR 6.14 (95% CI 2.35 to 16.08) and HR 5.06 (95% CI 1.88 to 13.63) as compared with MVC and non-GSW assault cohorts, respectively). Homicide was the cause of death in 79.2% of GSW patients who died after surviving the index injury.

Conclusion Among individuals presenting to the ED after injury or assault and surviving to discharge, firearm injury exposure is an important predictor of death within 5 years and most pronounced in the first year after injury.