BackgroundFirearm trauma remain a national crisis disproportionally impacting minority populations in the United States. Risk factors leading to unplanned readmission after firearm injury remain unclear. We hypothesized that socioeconomic factors have a major impact on unplanned readmission following assault-related firearm injury. MethodsThe 2016–2019 Nationwide Readmission Database of the Healthcare Cost and Utilization Project was used to identify hospital admissions in those aged >14 years with assault-related firearm injury. Multivariable analysis assessed factors associated with unplanned 90-day readmission. ResultsOver 4 years, 20,666 assault-related firearm injury admissions were identified that resulted in 2,033 injuries with subsequent 90-day unplanned readmission. Those with readmissions tended to be older (31.9 vs 30.3 years), had a drug or alcohol diagnosis at primary hospitalization (27.1% vs 24.1%), and had longer hospital stays at primary hospitalization (15.5 vs 8.1 days) [all P<0.05]. The mortality rate in the primary hospitalization was 4.5%. Primary readmission diagnoses included: complications (29.6%), infection (14.5%), mental health (4.4%), trauma (15.6%), and chronic disease (30.6%). Over half of the patients readmitted with a trauma diagnosis were coded as new trauma encounters. 10.3% of readmission diagnoses included an additional ‘initial’ firearm injury diagnosis. Independent predictors of 90-day unplanned readmission were public insurance (aOR 1.21, P = 0.008), lowest income quartile (aOR 1.23, P = 0.048), living in a larger urban region (aOR 1.49, P = 0.01), discharge requiring additional care (aOR 1.61, P < 0.001), and discharge against medical advice (aOR 2.39, P < 0.001). ConclusionsHere we present socioeconomic risk factors for unplanned readmission after assault-related firearm injury. Better understanding of this population can lead to improved outcomes, decreased readmissions, and decreased financial burden on hospitals and patients. Hospital-based violence intervention programs may use this to target mitigating intervention programs in this population.