Background:

Patients with mild traumatic brain injury can to some extend experience long-term physical, cognitive, social and behavioral deficits, which have serious implications for employment trajectories and financial independence. These deficits have shown to be more pronounced in women. High socio-economic position such as income, level of education and employment status before the accident have shown to affect return to work. But also cohabitation status, ethnicity and health are important factors. Previously studies are typically self-report studies, and are often small and may suffer from selection bias due to patient nonresponse.

Aim:

The aim of this study is to describe no return to work among patients with mild traumatic brain injury in Denmark and to examine how factors such as age, gender, cohabitation status, socio-economic and pre-injury health factors affect no return to work up to 5 years post-injury.

Hypothesis:

We hypothesize that most patients with mild traumatic brain injury return to work within work 6 months post-injury, and that patients with mild traumatic brain injury injury receive more social transfer payments compared to the general population.

Additionally, we hypothesize that low socio economic position, comorbidities and being single are associated with prolonged no return to work.

Methods:

The present study is an observational national register-based cohort study with long-term follow up of patients with mild traumatic brain injury from 1st of January 2008 - 31st of December 2012 in Denmark. Patients aged 18-60 years diagnosed with concussion from 1st of January 2003-31st of December 2007 in the national patient register will be included in the study. Data will be retrieved from several national databases, including the DREAM database containing data on social benefits and reimbursements.

Primary outcome is no-return to work (nRTW) due to any cause and the following four secondary outcomes are graded and should be regarded as a continuum ranging from health related nRTW, limited nRTW, permanently nRTW and mortality.

The results will be published as two separate scientific articles.

Inclusion Criteria:

• ICD-10 code for concussion as action diagnosis (ICD-10: S06.0)
• Working age adults between 18-60 years old at the time of injury
• Gainfully occupied or deemed available for work the week preceding the time of injury

Exclusion Criteria:

• Patients were excluded if they were hospital treated and diagnosed with other major neurological injuries such as spinal cord and column injuries and traumatic brain injuries (TBI) besides the concussion at baseline.
• Patients were excluded, who 5 years prior to baseline (1st of January 1998 - 31st of December 2002) had sustained major neurological impairments including concussions.
• Patients outside of the age limit
• Patients not resident in Denmark
• Patients on unemployment benefits and not economically active at the time of injury

Patients with mild traumatic brain injury were hospital admitted, emergency or outpatient treated and identified on the basis of ICD-10 codes in the National Patient Register from the 1st of January 2003 - 31st of December 2007.

Patients were included if they were registered in the national patient register database with concussion (ICD-10 S06.0) as primary diagnosis.