Premorbid risk factors influencing labour market attachment after mild traumatic brain injury: a national register study with long-term follow-up

OBJECTIVES: Some patients with mild traumatic brain injury (mTBI) experience persistent postconcussive symptoms, influencing the ability to work. This study assessed associations between mTBI and labour market attachment (up to 5 years postinjury) in patients with different premorbid characteristics. DESIGN AND SETTING: Danish national cohort study with 5-year register follow-up. PARTICIPANTS: We included hospital admitted patients between 18 and 60 years diagnosed with mTBI (International Classification of Diseases, version 10 diagnosis S06.0) (n=19 732). For each patient, one control was selected matched on age, gender and municipality (n=18 640). PRIMARY OUTCOME MEASURE: Primary outcome was ‘not attending ordinary work’, and premorbid risk factors were cohabitation status, education, ethnicity, gender, age and comorbidities. RESULTS: The odds of not attending ordinary work increased from 6 months to 5 years. The highest increased odds (approximately twice as high for patients) of not attending ordinary work at 5 years were found in the highest educational group (OR 2.15, 95% CI 1.78 to 2.59), for patients of non-Danish origin (OR 1.98, 95% CI 1.52 to 2.57), for patients between 30 and 39 years (OR 1.93, 95% CI 1.68 to 1.23) and for patients with somatic comorbidities (OR 1.81, 95% CI 1.38 to 2.37). Contrary to expectations, we did not find higher odds in patients with psychiatric diagnoses (OR 1.12, 95% CI 0.76 to 1.60). CONCLUSIONS: Important premorbid characteristics for lower labour market participation after mTBI were higher education, non-Danish origin, age 30–39 years and having somatic comorbidities. Demographic and health-related variables should be considered when assessing patients with mTBI at risk of long-term sickness absence. TRIAL REGISTRATION NUMBER: NCT03214432; Results.