Association between spine injury and opioid misuse in a prospective cohort of Level I trauma patients

OBJECTIVE: To explore patient and treatment factors explaining the association between spine injury and opioid misuse. DESIGN: Prospective cohort study. SETTING: Level I trauma center in a Midwestern city. PARTICIPANTS: English speaking patients aged 18 to 75 on Trauma and Orthopedic Surgical Services receiving opioids during hospitalization and prescribed at discharge. EXPOSURE: Spine injury on the Abbreviated Injury Scale. MAIN OUTCOME MEASURES: Opioid misuse was defined by using opioids: in a larger dose, more often, or longer than prescribed; via a non-prescribed route; from someone other than a prescriber; and/or use of heroin or opium. Exploratory factor groups included demographic, psychiatric, pain, and treatment factors. Multivariable logistic regression estimated the association between spine injury and opioid misuse when adjusting for each factor group. RESULTS: Two hundred eighty-five eligible participants consented of which 258 had baseline injury location data and 224 had follow up opioid misuse data. Most participants were male (67.8%), white (85.3%) and on average 43.1 years old. One-quarter had a spine injury (25.2%). Of those completing follow-up measures, 14 (6.3%) developed misuse. Treatment factors (injury severity, intubation, and hospital length of stay) were significantly associated with spine injury. Spine injury significantly predicted opioid misuse [odds ratio [OR] 3.20, 95% confidence interval [CI] (1.05, 9.78)]. In multivariable models, adjusting for treatment factors attenuated the association between spine injury and opioid misuse, primarily explained by length of stay. CONCLUSION: Spine injury exhibits a complex association with opioid misuse that predominantly operates through treatment factors. Spine injury patients may represent a subpopulation requiring early intervention to prevent opioid misuse.