Return to work after early part-time sick leave due to musculoskeletal disorders: randomised controlled trial

Introduction: Musculoskeletal disorders are a major cause of disability in working populations. Recent guidelines on e.g. low back and neck pain emphasise the importance of staying active in preventing further disability. Part-time sick leave offers a possibility to be occupationally active when a disorder is causing partial work disability. Studies on the effects of part-time sick leave have given inconsistent results.  Objective: This study aimed at assessing the effects of early part-time sick leave as an intervention on return to work and subsequent sickness absence in patients with musculoskeletal disorders.  

Methods: A randomised controlled trial was conducted in the occupational health units of six enterprises. Patients aged 18-60 with musculoskeletal disorders (n=63) unable to perform their regular work were randomly allocated to part-time or full-time sick leave. In the former group, work time was reduced by about a half. Remaining tasks were modified when necessary, as specified in a fit note by the physician. The main outcomes were time to return to regular work activities and sickness absence during 12-month follow-up.  

Results: Time to return to work sustained for at least 4 weeks was shorter in the intervention group (median 12 vs. 20 days, p=0.10). Hazard ratio for return to work was 1.5 (unadjusted, 95% confidence interval 0.9-2.6) and 1.7 (1.2-2.4) adjusted for pain and disability related factors at baseline. Total sickness absence during the 12-month follow-up was about 20% lower in the intervention than the control group. Compliance with the intervention was high with no discontinuations of part-time sick leave due to musculoskeletal reasons.  

Conclusion: Early part-time sick leave may provide a faster and more sustainable return to regular duties than full-time sick leave in patients with musculoskeletal disorders. This is the first study to show that work participation can be safely increased with early part-time sick leave.