Ana Mikolic

Traumatic brain injury (TBI) is a sudden change in brain function or damage to the brain, caused by an external force. TBI represents a global public health problem and an important cause of morbidity. According to the most often used severity classification (Glasgow Coma Score), the majority of patients present with a mild TBI. A substantial proportion of “mild” TBI patients do not completely return to their preinjury functioning, such as work, social and leisure activities, months after injury. They frequently experience persistent cognitive (e.g. forgetfulness), somatic (e.g. headache) and emotional (e.g. irritability) symptoms called post-concussion symptoms, and symptoms of mental health disorders often (co-)occur. The initial TBI severity is not the only factor impacting clinical decisions and patient outcomes following TBI. Treatment and outcome can vary based on other clinical and personal characteristics. TBI studies suggest outcome differences between men and women, but the direction and size of differences vary. Because of an aging population, older adults represent a growing TBI population. Increased age and the presence of mental and physical comorbidities can influence treatment and outcome.

Complex associations between different types of personal and clinical variables challenge the prediction of outcome after mild TBI. Clinical decision rules based on clinical variables have been developed for selecting mild TBI patients for computed tomography (CT) but need further optimization. Models for the prognosis of long-term outcomes following mild TBI have been rarely examined in new cohorts (externally validated) and robust prognostic models are currently unavailable. It is important to improve the identification of mild TBI patients at risk of acute (e.g. intracranial pathology) and persistent complications (e.g. recurrence of lesions, post-concussion symptoms and incomplete recovery) to inform patients and provide adequate treatment.

The overall aims of this thesis were to describe the treatment and outcome of (mild) TBI in relation to sex/gender, age and comorbidity (Part 1) and to improve diagnosis and prognosis following mild TBI (Part 2). To achieve our aims, we mainly used the Collaborative European NeuroTrauma Effectiveness Research in TBI (CENTER-TBI) Core study, which is a Europe-based multicenter, longitudinal, prospective, observational trial that included 4509 TBI patients- including 2864 patients categorized as mild.

Part 1: Treatment and outcome of mild TBI: relations with sex/gender, age and comorbidity

Main findings
In Chapter 2, we described care pathways, treatment and outcome in relation to sex/