BACKGROUND: Systemic inflammation is hypothesized to contribute to post-traumatic stress disorder (PTSD) vulnerability. Few studies have examined inflammation shortly after trauma as a predictor of later PTSD symptoms. We examined whether inflammation from the emergency department (ED) post-trauma is associated with PTSD symptom severity over the following 6 months.

METHODS: Our sample included 742 AURORA participants, a longitudinal cohort of patients in 29 EDs across the United States after a traumatic stressor, followed up to 6 months. Plasma cytokines were assessed from a study blood draw in the ED: an inflammatory index (standardized sum of generally pro-inflammatory markers interleukin [IL]-6, IL-8, tumor necrosis factor alpha [TNF-α], interferon gamma [IFN-γ]), and generally anti-inflammatory IL-10. PTSD symptoms were self-reported at 2 weeks, 8 weeks, 3 months, and 6 months post-ED. Covariate-adjusted repeated-measures regressions estimated associations between inflammation and PTSD symptoms, overall and sex-stratified.

RESULTS: Among 742 participants (age  = 40.0 [13.7]; 479 [64.6%] female), PTSD symptoms were elevated then modestly decreased over follow-up. Higher ED inflammation was associated with higher PTSD symptoms across follow-up (standardized symptoms  = 0.05, 95% CI: 0.01-0.09), adjusted for potential confounders. Higher pro-inflammatory index levels and IL-6, IL-8, and TNF-α were associated with higher PTSD symptoms in males only, while higher IL-10 was associated with higher PTSD symptoms in females only.

CONCLUSIONS: Pro-inflammatory levels shortly after traumatic stress are associated with heightened PTSD symptoms, particularly among males. Inflammatory markers may prove useful additions to prediction models for PTSD following trauma, with attention to sex differences.