Labour market attachment after mild traumatic brain injury: nationwide cohort study with 5-year register follow-up in Denmark

Objectives Sickness absence after mild traumatic brain injury (mTBI) is frequent due to postconcussive symptoms. We examined labour market attachment following mTBI up to 5 years postinjury. Design and setting Nationwide cohort study with register follow-up. Participants Patients between 18 and 60 years with mTBI (International Classification of Diseases, version 10 diagnosis S06.0) were extracted from the Danish National Patient Register (n= 19 732). Controls were matched on sex, age and municipality (n= 18 640). Patients with spinal cord and column injuries, traumatic brain injury and concussions 5 years preinjury or as secondary diagnosis to the concussion in the inclusion period were excluded. Primary and secondary outcome measures Data were extracted from the Danish Register for Evaluation of Marginalization. Primary outcome was 'not attending ordinary work' defined as receiving any social transfer payment. Secondary outcomes were health-related benefits, limited attachment to the labour market, permanent lack of attachment to the labour market and death. Results 5 years after diagnosis, 43% of patients were not attending ordinary work. The odds increased from 6 months (OR 1.30, 95% CI 1.24 to 1.36) to 5 years (OR 1.54, 95% CI 1.45 to 1.63). The odds of health-related benefits were 32% (OR 1.32, 95% CI 1.22 to 1.42) at 6 months and 22% (OR 1.22, 95% CI 1.12 to 1.33) at 5 years. Limited attachment to the labour market showed increased odds at 5 years (OR 1.38, 95% CI 1.27 to 1.51) and the odds of permanent lack of attachment to the labour market were higher for patients compared with controls (OR 2.59, 95% CI 2.30 to 2.92). Death was more than two times higher at 5 years postinjury (OR 2.62, 95% CI 2.10 to 3.26). Conclusions 43% of concussed patients were not attending ordinary work 5 years postinjury and received health and social transfer benefits. We conclude that mTBI has a long-term impact on labour market attachment. Prevention and treatment of persisting postconcussive symptoms should be considered. Trial registration number NCT03214432; Results