Purpose: In workers with musculoskeletal injuries, comorbidity is associated with worse return to work (RTW) outcomes. In the context of RTW, it is unclear whether associations between predictors and RTW are similar or different for workers with and without comorbidity. This study aims to investigate differences and similarities between workers with and without comorbidity in 12-month predictors for RTW in workers who are absent from work due to a musculoskeletal injury.
Methods: All workers with lost-time claims who were off work at baseline were selected from the Early Claimant Cohort (Canada) (n = 1,566). Follow-up data on RTW were available of 810 workers after 12 months. Predictors included demographic, health-related, and work-related factors. Differences between coefficients of the groups with and without comorbidity were tested.
Results: Low household income was a predictor for RTW in workers without comorbidity only. Better mental health was a predictor for RTW in workers with comorbidity only. Higher education, less pain intensity, better general health, less bodily pain, better physical health, and a positive supervisor response were predictors for RTW in the total group.
Conclusions: Injured workers with and without comorbidity should be considered as two distinct groups when focusing on mental health or household income.