The effects of marijuana use prior to traumatic brain injury on survival

Abstract

BackgroundLegalization of recreational marijuana throughout the United States has been associated with increased emergency department visits involving marijuana and its metabolites, tetrahydrocannabinol (THC) and cannabinoids. We investigated the relationship between marijuana use and outcomes after all levels of traumatic brain injury (TBI) from a large multi-center regional dataset. MethodsA retrospective review of de-identified patient data from twenty-six regional hospitals, was performed to identify adult patients with mild, moderate, and severe TBI between January 2012 and December 2018, a toxicology screen, and drug screen results. Included patients were divided into four subgroups: 1) No Drugs, 2) THC, 3) Other drugs (one or more drugs not including THC), and 4) THC + Other drugs. The primary outcome was mortality at discharge, while secondary outcomes included days in intensive care unit (ICU), length of hospital stay (LOS), and days on a ventilator. ResultsA total of 3,237 patients (median age 46 years [range: 18–97 years]; 31.9% female [1029/3,227]) met the inclusion criteria. Patients in the No Drugs group had significantly higher mortality rates at discharge than the THC (p = 0.0046), Other Drugs (p = 0.0307), and THC + Other Drugs groups (p = 0.0441). On multiple logistic regression, drug status was found not to be an independent predictor of mortality at discharge, while age, Glasgow Coma Scale (GCS), days in the ICU, Injury Severity Score (ISS), LOS, and days on a ventilator were independent predictors. ConclusionsPatients positive for one or more drugs, including marijuana, had significantly lower mortality at discharge than those with no drugs; however, after controlling for confounding variables, drug status was not found to be an independent predictor of mortality at discharge. Therefore, our results indicate no survival benefit for any level of TBI with concomitant drug use, including marijuana, in contrast to recent studies. Level of Evidence[Level III Prognostic and Epidemiological Study] - Prognostic.