Housing status and longitudinal care patterns after injury

STUDY OBJECTIVE: Injury is a leading cause of hospitalization in people experiencing homelessness, yet post-injury care use is unknown. We sought to understand care use patterns in the 12 months after injury in people experiencing homelessness versus housed low-income Medicaid beneficiaries. 

METHODS: We conducted a retrospective cohort study examining injured Medicaid beneficiaries in San Francisco from 2015 to 2022. Our primary exposure was housing status at the time of injury, obtained from linking the county's only Level 1 Trauma Center's Trauma Registry to the county-wide Coordinated Care Management System integrated data system. The primary outcome was emergency department (ED) visits in the 12 months after injury. Secondary outcomes were hospital admissions, outpatient visits, and mental health encounters. We adjusted for demographic, clinical, and injury variables as well as preinjury care use. 

RESULTS: Among 5,998 people, 32.9% (N=1,926) were experiencing homelessness at injury. Approximately 76.9% were men, 82.3% spoke English, and 26.9% were Black. Thirty-four percent of people experiencing homelessness had 4 or more ED visits in the 12 months following injury. People experiencing homelessness had a 0.99 greater adjusted increase in ED visits after injury compared with before injury versus housed low-income Medicaid beneficiaries (95% confidence interval 0.64 to 1.33; P<.001). This pattern was observed for inpatient admissions, outpatient visits, and mental health encounters. ED visits and mental health encounters persisted above preinjury levels for 12 months following injury for people experiencing homelessness. 

CONCLUSION: The 12 months following injury had higher health-sector use among those experiencing homelessness than housed low-income Medicaid beneficiaries.