(323) Substance Use Disorders and Mortality in Traumatic Brain Injuries: A Population-Level Analysis

Introduction: Substance use disorders (SUD) before or after traumatic brain injuries (TBI) are associated with diminished recovery. The population level impact of SUD on mortality following TBI has not been determined.

Methods: We used publicly available, statewide, and deidentified hospitalization records to study patients aged ≥18 years with a principal diagnosis of an initial encounter for TBI at acute care hospitals in Texas from 2016 through 2022. Hospitalizations with a diagnosis of TBI were identified using Clinical Classification Software Refined category INJ009: Traumatic Brain Injury: Initial Encounter. Three models estimated the association between SUD and in-hospital mortality. Multilevel logistic regression with propensity adjustment was the primary analysis approach with propensity score matching and multivariable logistic regression applied as alternative analyses. Risk adjustment covariates included demographics, Deyo modification of Charlson comorbidities, medical procedures, injury severity, hospital teaching status, mechanism of injury, and intent of injury. Additional analyses were completed for patient subgroups, sensitivity, and for the secondary outcome of short-term mortality defined as in-hospital mortality or discharge to hospice.

Results: Out of 90,405 hospitalizations with a principal diagnosis of TBI, 7,649 (8.5%) had SUD. TBI hospitalizations with vs without a SUD were younger (39.3% vs 20.6% aged ≤44 years), less often white (51.3% vs 56.5%), less frequently had diabetes (17.2% vs 24.9%), had higher rates of mental disorders (26.0% vs 17.1%), and were more often uninsured (32.9% vs 16.6%); p < 0.0001 for each. Unadjusted in-hospital mortality for TBI patients with and without a SUD was 6.2% vs 9.0%. On adjusted analyses, SUD remained associated with lower odds of short-term mortality (adjusted odds ratio 0.5767 [95% CI 0.5111–0.6506]). The results were similar for the alternative modeling approaches, subgroup analyses, and the secondary outcome of short-term mortality.

Conclusions: SUD was associated with lower risk of both in-hospital and short-term mortality for TBI hospitalizations. Studies exploring the mechanisms leading to these findings will improve understanding of mortality following TBI.