Health status, work limitations, and return-to-work trajectories in injured workers with musculoskeletal disorders

WSIB data files are consolidated and stable only at 6 months post-injury. At that time point, an algorithm mimicking our initial inclusion criteria was applied to the entire WSIB claimant population who registered a claim during the study’s baseline data collection period. The algorithm mimicked the following inclusion criteria: work absence duration, site of injury, nature of injury, age. Due to the nature of WSIB data, benefit information is collected continuously only for accepted claims. In that regard, this is not a perfectly comparable group for our cohort, as our cohort also includes denied and abandoned claims. However, it remains the best comparison group available to investigate the representativeness of the cohort. In order to adjust for the absence of information on denied and abandoned claims in the WSIB files, we also applied the algorithm to the cohort. While all 632 participants met inclusion criteria at time of baseline interview, only 66% (n = 415) of our cohort met the algorithm-based criteria 6 month post-injury. There are two main reasons for this. First, our inclusion criterion was registration of a lost-time claim, not its acceptance (our cohort includes denied/abandoned claims), and the algorithm could only select accepted lost-time claims. Second, our inclusion criterion was a minimum of five self-reported days of absence in the first 14 days, while the algorithm selected a minimum of 5 days on benefits during the first 14 days. This allowed for claimants who missed 5 or more days of work in the first 14 days post-injury, with no compensation, to be included in the cohort.