Return to Work After Mild Traumatic Brain Injury

Study Overview
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Brief Summary
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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.

Official Title
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Return to Work After Mild Traumatic Brain Injury

Conditions
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Mild Traumatic Brain Injury, Concussion, Mild

Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| mild traumatic brain injury cohort<br>Patients with mild traumatic brain injury were defined as hospital admitted, emergency or outpatient treated, who were assigned the ICD-10 code for concussion (ICD-10 S06.0) in the national patient register at hospital discharge from the 1st of January 2003 - 31st of December 2007. Patients were working age adults between 18-60 years old and gainfully occupied or deemed available for work the week before the injury. | |
| non-injured control group<br>Controls were randomly selected from the Population register who were between 18-60 years old, had no diagnosis of mild traumatic brain injury during the period 1st of January 2003 - 31st of December 2007 and were gainfully occupied or deemed available for work the week preceding the time of injury. One control was matched for each mTBI case on gender, municipality and age (year of birth +/- 0,5 years). In case of no matching control the age criterion was expanded to (year of birth +/- 1 year), if still no matching control the age criterion was further expanded to (year of birth +/- 2 year). Additionally, controls were excluded according to the same criteria as the included cases. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| nRTW | No-return to work up to 5 years post-injury. nRTW is defined as receiving social transfer payments in any given week during the follow-up period. If no social benefit is given in the DREAM register, it is assumed the patient is gainfully occupied or self-supporting. | 5 years follow up | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Health related nRTW | Health related nRTW is defined as a combined effect of social transfer payments given in case of short or long-term sickness absence. If social transfer payments are granted due to illness it is assumed that the patient is not gainfully working or job seeking. | 5 years follow up | 
| Limited nRTW | Limited nRTW is defined as a joint effect of several outcome measures granted citizens with permanent reduced work capacity. If no social transfer payments are given, it is assumed that the patients are gainfully occupied or self-supporting. | 5 years follow up | 
| Permanently nRTW | Individuals between 18-60 years who have permanently reduced work capacity and unable to return to work after injury can be granted disability pension (DP) after an extensive municipal assessment. DP would only be granted persons who have no work capacity left. This outcome includes disability pension and mortality and is regarded as a permanent exit from the labour market. | 5 years follow up | 
| Mortality | Data on mortality was retrieved from the DREAM register and the proportion of mortality will be assessed during the 5 year follow-up period. | 5 years follow up | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Mild traumatic brain injury, Concussion, Labour market affiliation, Return to work, Sickness absence, Long-term sickness absence, Disability pension