Patterns of Alcohol and Drug Screening in Trauma Patients: Understanding Housing Status as a Determinant of Care

Background: Traumatic injury remains a leading cause of morbidity and mortality in the United States, with substance use and social determinants of health playing important roles in injury risk and clinical outcomes. People experiencing homelessness are disproportionately exposed to trauma and are screened for alcohol and drugs at higher rates than housed patients, raising questions about whether differences in substance positivity reflect true variation in exposure or disparities in screening practices. This study examines patterns of alcohol and drug screening and positivity among housed and unhoused trauma patients, with particular attention to polysubstance use. Methods: We conducted a retrospective cross-sectional analysis of adult trauma patients included in the 2021 National Trauma Data Bank. Alcohol and drug screening within the first 24 hours of hospital encounter were examined, along with screening results and the presence of multiple concurrent drug positives. Homelessness was the primary exposure of interest. Multivariable logistic regression models were used to assess the association between housing status and screening practices as well as positive alcohol, drug, and polydrug results, adjusting for age, sex, race, ethnicity, injury severity, Glasgow Coma Scale score, physical and behavioral comorbidities. Results: Among 1,000,269 adult trauma patients, 9,466 (0.9%) were unhoused. Unhoused patients were significantly more likely to be screened for alcohol and drugs than housed patients. After adjustment, homelessness remained the strongest predictor of screening for both alcohol and drugs. Among those screened, homelessness was associated with markedly higher odds of positive drug and polydrug results, the association with positive blood alcohol concentration was modest despite substantially higher screening rates. Injury severity and lower Glasgow Coma Scale scores were also associated with increased screening and positivity. Conclusions: Unhoused trauma patients experience substantially higher rates of alcohol and drug screening and higher odds of drug and polysubstance positivity compared with housed patients. These findings suggest that housing status strongly shapes diagnostic practices in trauma care and may influence the interpretation of substance use epidemiology. Standardized, non-stigmatizing screening approaches that are paired with appropriate clinical and social interventions are needed to ensure equitable trauma care.