Effect of Partial Sick Leave on Sick Leave Duration in Employees with Musculoskeletal Disorders.

This is an observational study, so it shows associations and cannot prove that partial sick leave caused longer or shorter sick leave duration. The analysis used data from occupational health checks and sick leave registers with 12 months of follow-up, and some confounders may have changed between the health check and the sick leave episode. There was a lot of missing data: percentages of missing values per variable ranged from 0 to 34.5%, and 46% of cases were incomplete for the selected variables. Partial sick leave was simplified into yes or no, so employees who worked a little and employees who worked almost full hours were treated the same. The study had no information on adjustment of work tasks, received treatments or interventions, occupation, or comorbidity, all of which could influence sick leave duration. Only employees sick-listed for at least 4 weeks were included, so the study cannot tell what happens with shorter sick leave episodes. 79.6% of employees had partial sick leave, which may reflect Dutch legislation requiring employees to accept modified duties rather than a voluntary clinical recommendation. Timing analyses compared groups defined by minimum sick leave duration, so employees in the 180-day subset already had at least 180 days of sick leave by design.

Do not conclude that partial sick leave causes shorter sick leave duration. This was an observational study, and the main adjusted association was longer duration. The shorter duration finding came only from employees already sick for at least 180 days starting between 91 and 180 days.