The Burden of Work Disability Associated with Mild Traumatic Brain Injury in Ontario Compensated Workers: A Prospective Cohort Study

Objectives: To estimate the incidence of compensated claims involving mild traumatic brain injury among On- tario workers covered by the Workplace Safety & Insurance Board (WSIB) and to describe the number and duration of days off work related to incident claims using workers compensation administrative data. Methods: We used a population-based, historical cohort of 111,800 injured workers aged 20 or older with a claim to the Ontario Workers' Safety and Insurance Board in 1998. We estimated the incidence as the rate of new mild traumatic brain injury in the Ontario working population eligible for compensation by the WSIB. We described the number and duration of disability days using an episodic and cumulative analysis of time on benefits over a two-year period (1997-98) deter- mined from administrative data. Results: The annual incidence was 1.5 (95% CI: 1.3, 1.7) per 10,000 full-time equivalents. Eighty-seven percent of claim- ants had a single episode of benefits with median duration of 11 days (95% CI: 10, 12). Fifty percent were off benefits af- ter 17 days and 75% by 72 days. Conclusions: Mild traumatic brain injury is disabling in the working population. Most work disability is short-term, but a small proportion of claimants become chronically disabled and unable to work.