Interrelationships Between Post-TBI Employment and Substance Abuse: A Cross-lagged Structural Equation Modeling Analysis

Objective: To describe the interrelationship of postinjury employment and substance abuse (SA) among individuals with traumatic brain injury. Design: Structural equation model (SEM) and logistic regression analytic approach using a merged database of the National Trauma Data Bank (NTDB) and Traumatic Brain Injury Model Systems (TBIMS) National Database, with acute care and rehabilitation hospitalization data and 1, 2, and 5 year follow-up data. Setting: United States Level I/II trauma centers and inpatient rehabilitation centers with telephone follow-up. Participants: Individuals in the TBIMS National Database successfully matched to their NTDB data, aged 18-59 years, with trauma severity, age, sex, employment, and SA data at 1, 2, and/or 5 years postinjury (N=2890). Interventions: Not applicable. Main Outcome Measure: Employment status (employed/unemployed) and SA (present/absent) at year 1, year 2, and year 5 postinjury. Results: SEM analysis showed older age at injury predicted lower likelihood of employment at all time points postinjury (beta(YR1)= -0.016; beta(YR2)=-0.006; beta(YR5)=-0.016; all P<.001), while higher injury severity score (ISS) predicted lower likelihood of employment (beta=-0.008; P=.027) and SA (beta=-0.007; P=.050) at year 1. Male sex predicted higher likelihood of SA at each follow-up (beta(YR1)=0.227; beta(YR2)=0.184; beta(YR5)=0.161; all P<.100). Despite associations of preinjury unemployment with higher preinjury SA, postinjury employment at year 1 predicted SA at year 2 (beta=0.118; P=.028). Employment and SA during the previous follow-up period predicted subsequent employment and SA, respectively. Conclusions: Employment and SA have unique longitudinal interrelationships and are additionally influenced by age, sex, and ISS. The present work suggests the need for more research on causal, confounding, and mediating factors and appropriate screening and intervention tools that minimize SA and facilitate successful employment (C) 2019 by the American Congress of Rehabilitation Medicine