Objectives The purpose of this study was to assess the effects of early part-time sick leave on return to work (RTW) and sickness absence among patients with musculoskeletal disorders.
Methods A randomized controlled trial was conducted in six occupational health units of medium- and large-size enterprises. Patients aged 18–60 years with musculoskeletal disorders (N=63) unable to perform their regular work were randomly allocated to part- or full-time sick leave. In the former group, workload was reduced by restricting work time by about a half. Remaining work tasks were modified when necessary, as specified in a “fit note” from the physician. The main outcomes were time to return to regular work activities and sickness absence during 12-month follow-up.

Results Time to RTW sustained for ≥4 weeks was shorter in the intervention group (median 12 versus 20 days, P=0.10). Hazard ratio of RTW adjusted for age was 1.60 [95% confidence interval (95% CI) 0.98–2.63] and 1.76 (95% CI 1.21–2.56) after further adjustment for pain interference with sleep and previous sickness absence 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.

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

Key terms fit note; intervention study; MSD; musculoskeletal disease; musculoskeletal disorder; occupational health practice; randomized controlled trial; RCT; return to work; RTW; sick leave; sickness absence; sickness absence; work ability