Suicide and self-injury-related emergency department visits and homelessness among adults 25-64 years old from 2016 to 2021 in the USA.

Background: Despite pronounced increases in homelessness and mental health problems in the USA over the past decade, further exacerbated during the pandemic, and the higher prevalence of mental health conditions among individuals experiencing homelessness, no study has examined trends in self-injury-related ED visits by individuals experiencing homelessness using up-to-date nationwide data. To address this gap, we aimed to investigate the association of self-injury-related ED visits with homelessness and to examine trends in these ED visits by individuals experiencing homelessness.

Methods: We conducted a retrospective secondary data analysis using a nationally representative sample of ED visits by adults aged 25-64 years in the USA from the 2016-2021 National Hospital Ambulatory Medical Care Survey. We examined whether intentional self-injury-related ED visits and hospitalisations resulting from an ED visit were associated with homeless status using survey-weighted multivariable generalised linear regression models and whether trends in such visits changed over the study period.

Results: Our analysis covered 419.4 million ED visits from 2016 to 2021. Individuals experiencing homelessness constituted 1.8% (7.4 million) of ED visits. Overall, 1.8% of ED visits (7.7 million) were related to intentional self-injuries. Nearly 1 in every 10 ED visits (9.6%) by individuals experiencing homelessness were related to self-injuries, compared with 1.7% among housed counterparts (p<0.001). The adjusted incidence rate ratio for self-injury-related ED visits was 3.14 (95% CI 2.05 to 4.83) for individuals experiencing homelessness compared with housed individuals. Finally, individuals experiencing homelessness accounted for 12.0% and 11.7% of self-injury-related ED visits in 2020 and 2021, respectively (pandemic years), compared with an average of 8.4% in the previous years.

Conclusion: Among adults aged 25-64 years, experiencing homelessness was significantly associated with self-injury-related ED visits, and an increase in the rate of such visits among individuals experiencing homelessness was observed during 2020 and 2021. Future studies should assess longer-term trends in these visits and explore interventions to address the societal, health and mental healthcare needs in order to improve the health outcomes of these marginalised individuals.