Title:
Elevated C-reactive protein levels may be a predictor of persistent unfavourable symptoms in patients with mild traumatic brain injury: a preliminary study.

Abstract:
The pathogenesis of persistent unfavourable outcomes following mild traumatic brain injury (mTBI) are not fully understood. Low-grade systemic inflammation might contribute to the development of persistent unfavourable outcomes in patients with mTBI. We used plasma high-sensitivity C-reactive protein (CRP) levels as the biomarker of systemic inflammation to investigate whether elevated CRP levels were associated with persistent adverse outcomes in these patients. A total of 213 consecutive patients with mTBI were identified in our study. Plasma high-sensitivity CRP levels were measured at baseline, 1month, 2months and 3months after initial traumatic brain injury. The study endpoints included persistent postconcussion syndrome (PCS), persistent psychological problems (depression and anxiety), persistent physiological problems (frequent headache, nausea, insomnia, dizziness and fatigue) and persistent cognitive impairment, which were screened by International Classification of Diseases (ICD-10), diagnostic and statistical manual of mental disorders (DSM-IV), Beck anxiety inventory (BAI), Beck depression inventory (BDI) and montreal cognitive assessment (MoCA) 3months post-injury. The associations between baseline CRP levels and persistent unfavourable outcomes were estimated from multiple regression models adjusting for various confounding covariates. Elevated baseline CRP levels were associated with a significant increase in the incidence of persistent PCS (odds ratio [OR], 2.719; 95% confidence interval [CI], 1.609-4.594; p=0.000), persistent psychological problems (OR, 1.535; 95% CI, 1.063-2.216; p=0.022), and persistent cognitive impairment (OR, 1.687; 95% CI, 1.135-2.507; p=0.010). However, elevated CRP levels were not associated with persistent physiological problems (OR, 1.330; 95% CI, 0.905-1.956; p=0.146). Furthermore, three adjusted models did not essentially affect the OR of elevated CRP levels for these persistent unfavourable outcomes. Among patients with mTBI, baseline elevated CRP levels may be an independent predictor of persistent persistent PCS, psychological problems and cognitive impairment.