Association between social vulnerability, urbanicity, and post-injury outcomes following nonfatal motor vehicle...

Motor vehicle crashes (MVCs) are a leading cause of injury and death in the United States. Community-level factors, such as social vulnerability and urbanicity, have been associated with risk of death; less is known about how these factors impact nonfatal, post-injury outcomes. This study examined the association between social vulnerability and urbanicity with hospital length of stay (LOS) and hospital discharge disposition among MVC patients.

Patients aged 18 years and older who were admitted to a Montana regional trauma center with a non-fatal injury following an MVC from 2016 to 2024 were included in the study. The CDC Social Vulnerability Index (SVI) was used to quantify social vulnerability at the census tract level and scores were divided into tertiles representing low, medium, and high vulnerability. Urbanicity was defined using RUCA codes based on patient residence. Generalized estimating equations with a binomial distribution were used to estimate the joint association between SVI and urbanicity with discharge disposition (home vs. facility) and prolonged LOS (≥7 days), controlling for injury severity, patient demographics, and comorbidities.

Of the 668 patients, 529 (79%) were discharged home and 179 (27%) had a prolonged LOS. Among metropolitan patients, higher SVI rankings were associated with increased odds of discharge home; patients with medium and high SVI had respectively 2.6 and over 3 times greater odds of being discharged home than low SVI (medium aOR: 2.64; 95% CI: 1.96, 3.57; high aOR: 3.26; 95% CI: 2.52, 4.23). This association was not observed for non-metropolitan patients; however, patients from non-metropolitan had 2 times the odds of a prolonged LOS than those from metropolitan areas regardless of SVI (aOR: 2.03; 95% CI: 1.38, 2.98).

The association between social vulnerability and discharge disposition following a MVC differed by urbanicity, and urbanicity was also associated with prolonged LOS. Further research to better understand how sociodemographic factors impact nonfatal injury outcomes can help reduce disparities in care.