Influence of Neighborhood Disadvantage on All-Cause Mortality Following Moderate-to-Severe Traumatic Brain Injury: A TBI Model Systems Cohort Study.

Objective: To examine associations between neighborhood disadvantage and all-cause mortality among patients receiving inpatient rehabilitation for moderate-to-severe traumatic brain injury (msTBI).

Setting: Participants who were discharged from inpatient rehabilitation at a Traumatic Brain Injury Model Systems (TBIMS) center.

Participants: A total of 6634 individuals enrolled in the TBI Model Systems National Database, who were discharged from inpatient rehabilitation for msTBI between January 1, 2010, and December 31, 2018.

Design: Secondary analysis of longitudinal data.

Main measures: All-cause mortality served as the primary outcome variable, measured in years from the date of discharge to the date of either expiration or censorship, with follow-up through December 31, 2019. Due to proportional hazards violations, we fit separate models for early deaths (within 4 months post-discharge) and late deaths (after 4 months post-discharge). Neighborhood disadvantage was indicated by the Distressed Communities Index (DCI), a validated measure that compares the socioeconomic conditions of United States ZIP codes.

Results: Neighborhood distress level did not significantly influence early mortality risk in either univariate or multivariable Cox proportional hazards models. However, when examining deaths occurring 4 months to 10 years post-discharge, a significant association emerged. Residing in Distressed neighborhoods was linked to an increased mortality risk. In the model adjusted for sociodemographic factors, urban-rural classification, and baseline health and injury characteristics, individuals in Distressed neighborhoods experienced a 28% higher risk of death compared to those in Prosperous neighborhoods (HR: 1.28; 95% CI: 1.01-1.62). This association was somewhat attenuated and no longer significant (P = .09) after further adjusting for functional independence at discharge (Cognitive and Motor FIM) (HR: 1.22; 95% CI: 0.96-1.55).

Conclusions: This study contributes to the literature by examining the role of neighborhood socioeconomic conditions on mortality risk following TBI, while controlling for established person-level risk factors. Our findings suggest that discharge to a distressed neighborhood is significantly associated with increased mortality risk among individuals who receive inpatient rehabilitation for msTBI and survive to at least 4 months post-injury. This heightened risk appears to be partly explained by reduced functional independence at discharge among those returning to disadvantaged neighborhoods. These results suggest that enhancing patients' functional independence during inpatient rehabilitation may help mitigate some of the excess mortality risk associated with adverse neighborhood conditions.