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

Abstract

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 (β_YR1=−0.016; β_YR2=−0.006; β_YR5=−0.016; all P<.001), while higher injury severity score (ISS) predicted lower likelihood of employment (β=−0.008; P=.027) and SA (β=−0.007; P=.050) at year 1. Male sex predicted higher likelihood of SA at each follow-up (β_YR1=0.227; β_YR2=0.184; β_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 (β=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-related outcomes.