Outcomes after traumatic injury in patients with preexisting psychiatric illness.

BACKGROUND: Patients with psychiatric illness have been shown to experience higher rates of traumatic injury. Injury patterns, treatment decisions, and outcomes have not been well characterized in patients with psychiatric illness after injury, in particular those who undergo acute surgical intervention. The purpose of this analysis was to determine mortality, complications, and surgical intervention rates in patients with psychiatric illness after traumatic injury.
METHODS: This is a retrospective study of trauma patients ≥18 years old admitted to LAC + USC Medical Center between January 2008 and March 2015. Patients with psychiatric diagnoses were identified using ICD-9 diagnosis codes. Multivariate logistic regression analyses taking into account demographic and injury characteristics were used to identify associations between psychiatric comorbidity, injury mechanism, surgical interventions, and outcomes in patients after injury.
RESULTS: A total of 26,502 patients were analyzed. Of these, 3,040 (11.5%) had a documented psychiatric comorbidity (2.0% depressive disorder, 0.8% bipolar disorder, 1.3% schizophrenia, 0.5% anxiety disorder, 3.2% substance use disorder). Patients with psychiatric illness were significantly older (49.6 years vs. 42.0 years, p < 0.001), had a lower proportion of penetrating injuries (13.8% vs. 18.1%, p < 0.001), and had a higher incidence of self-inflicted injuries (11.6% vs. 0.72%, p < 0.001). No difference in gender distribution was observed (74.2% men vs. 74.4% men, p = 0.80). Overall mortality was similar in both groups (adjusted odds ratio [aOR], 0.73; p = 0.07). Patients with psychiatric illness were significantly less likely to undergo acute surgical intervention within 6 hours of emergency department admission (aOR, 0.64; p < 0.001). Time from ED arrival to consent for acute surgical intervention was similar in both groups (94.8 min vs. 93.0 min, p = 0.84). No significant difference in mortality after acute surgical intervention was observed (aOR, 0.26; p = 0.10). Psychiatric illness was associated with a significantly higher likelihood of developing complications (aOR, 1.90; p < 0.001) and longer hospital lengths of stay (10.6 days vs. 6.2 days, p < 0.001).
CONCLUSIONS: Trauma patients with comorbid psychiatric illness were observed to have lower rates of acute surgical interventions, higher complication rates, and longer hospital lengths of stay. Further studies are needed to better characterize the causative factors underlying these associations. LEVEL OF EVIDENCE: Epidemiological, level III.