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CompletedNCT03214432Updated Jul 6, 2018

Return to Work After Mild Traumatic Brain Injury

An observational study in Mild Traumatic Brain Injury and Concussion, Mild, sponsored by University of Copenhagen. Completed at 1 site in Denmark. Open to participants aged 18 Years to 60 Years. Per ClinicalTrials.gov, last updated 2018-07-06.

Sponsored by University of Copenhagen · Observational

Study type
Observational
Model
Cohort
Time perspective
Retrospective
Enrollment
38,372
Ages
18 Years to 60 Years
Sex
All
01

Study summary

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.

02

Conditions studied

  • Mild Traumatic Brain Injury
  • Concussion, Mild

Keywords

  • Mild traumatic brain injury
  • Concussion
  • Labour market affiliation
  • Return to work
  • Sickness absence
  • Long-term sickness absence
  • Disability pension
03

In context

Brain Injuries

2,113 studies on the registry are indexed under Brain Injuries; 385 are open to participants now.

This study's enrollment of 38,372 is above the median of 100 across 690 observational studies indexed under Brain Injuries.

Browse Brain Injuries studies →

Lead sponsor

University of Copenhagen is the lead sponsor of 450 studies on the registry; 61 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years to 60 Years
Sexes eligible
All
Accepts healthy volunteers
No
Sampling method
Probability sample

Study population

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.

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

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
05

Study design

Observational model
Cohort
Time perspective
Retrospective
Enrollment
38,372 participants (actual)
Patient registry
No

Groups and cohorts

  • mild traumatic brain injury cohort

    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

    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.

06

What researchers measure

Primary outcomes

  1. 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.

    Time frame: 5 years follow up

Secondary outcomes

  1. 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.

    Time frame: 5 years follow up

  2. 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.

    Time frame: 5 years follow up

  3. 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.

    Time frame: 5 years follow up

  4. 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.

    Time frame: 5 years follow up

07

Study locations

1 site
  • Department of Psychology, University of Copenhagen
    Copenhagen, Copenhagen K 1353, Denmark
08

References and documents

Publications

  • Graff HJ, Siersma V, Moller A, Kragstrup J, Andersen LL, Egerod I, Mala Rytter H. Premorbid risk factors influencing labour market attachment after mild traumatic brain injury: a national register study with long-term follow-up. BMJ Open. 2019 Apr 11;9(4):e027297. doi: 10.1136/bmjopen-2018-027297. PubMed 30975684 ↗
  • Graff HJ, Siersma V, Moller A, Kragstrup J, Andersen LL, Egerod I, Mala Rytter H. Labour market attachment after mild traumatic brain injury: nationwide cohort study with 5-year register follow-up in Denmark. BMJ Open. 2019 Apr 11;9(4):e026104. doi: 10.1136/bmjopen-2018-026104. PubMed 30975680 ↗

Individual participant data

Plan to share: No

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Jul 6, 2018, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT03214432
Lead sponsor
University of Copenhagen
Collaborators
Rigshospitalet, Denmark, Sygekassernes Helsefond
Responsible party
Heidi Jeannet Graff (Ph.d. student, University of Copenhagen) — Principal investigator
First posted
Jul 11, 2017
Start date
Jul 1, 2017
Primary completion
Jul 4, 2018
Completion
Jul 4, 2018
Last update
Jul 6, 2018

Study contacts

Hana M Rytter
study director · Department of Psychology

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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