Pre-existing anxiety and depression disorders and return to work after musculoskeletal strain or sprain: a phased-based approach.

Purpose: To examine the impact of pre-existing anxiety and depression disorders on return to work (RTW) using a phase-based approach.

Methods: Accepted lost-time workers' compensation claims for upper limb or spine strain or sprain from 2009 to 2013 were extracted for workers in the Canadian province of British Columbia (n = 78,186). Pre-existing anxiety and depression disorders were identified using health claims data. Probability of RTW following a first or second work lost-time episode was analyzed using Prentice, Williams and Peterson models for recurrent events (common hazards ratios (cHR)). Probability of a first lost-time recurrence was analyzed using Cox models (HR). All models included two years of follow up and were stratified by gender.

Results: For men, anxiety alone (cHR = 0.90, 95% CI: 0.85 to 0.94) or comorbid with depression (cHR = 0.95, 95% CI: 0.92 to 0.99) was significantly associated with a lower probability of RTW, and comorbid anxiety and depression with a higher probability of recurrence (HR = 1.29, 95% CI: 1.13 to 1.48). In women, comorbid anxiety and depression was significantly associated with a lower probability of RTW (cHR = 0.96, 95% CI: 0.93 to 0.99) and a higher probability of recurrence (HR = 1.15, 95% CI: 1.04 to 1.28); and anxiety alone with a higher probability of recurrence (HR = 1.25, 95% CI: 1.09 to 1.43). There was little evidence that depression alone was associated with RTW or recurrence.

Conclusions: Workers with a pre-existing anxiety disorder may require additional supports both during lost-time and after initial RTW.