Does gradually returning to work improve time to sustainable work after a work-acquired musculoskeletal disorder in British Columbia, Canada? A matched cohort effectiveness study

Objective: This study investigates if gradual return to work (GRTW) is associated with full sustainable return to work (RTW) for seriously injured workers with a musculoskeletal disorder (MSD), in British Columbia, Canada. Methods: This is an effectiveness study using a retrospective cohort study design. Accepted workers' compensation lost-time claims were extracted for workers with an MSD who were on full work disability for at least 30 days, between 2010 and 2015 (n=37 356). Coarsened exact matching yielded a final matched cohort of 12 494 workers who experienced GRTW at any point 30 days post-injury and 12 494 workers without any GRTW. The association between GRTW and sustainable RTW through to end of 12 months was estimated with multivariable quantile regression. Results: Workers who were provided with GRTW experienced more time-loss days until sustainable RTW between the 2nd and 5th months after the first time-loss day (<50th quantile of time loss), but less time-loss days until sustainable RTW between the 6th and 12th months of work disability (70th quantile of time loss), with the largest effect for women, workers with soft-tissue injuries and workers in the manufacturing or trades sector (all in the 60th and 70th percentile, after 6-7 months of time loss). Conclusions: For seriously injured workers with at least 30 days of disability due to a work-acquired MSD, the effect of GRTW becomes apparent at longer disability durations (more than 6 months), with larger beneficial effects for women, workers with soft-tissue injuries and for trade and manufacturing sectors.