Discussion
The aim of the present study was to investigate whether the application of a standardised approach in a primary health care setting in patients with stress-related diagnoses could facilitate RTW. The findings point to the contrary: the PRIMA intervention appears to have protracted RTW times during the first year of follow-up. There was a significant difference in net sick leave days between cases and controls at three, six and 12 months after inclusion, where participants in the intervention group had more sick-leave days than those in the TAU group. At 24 months, the benefit of TAU for RTW could no longer be confirmed.Previous attempts have highlighted the challenges of designing interventions with significant return to work (RTW) benefits. A recent review study focusing on RTW interventions for burned-out employees found inconclusive evidence regarding their effectiveness in facilitating RTW [Another possible explanation for the results could be, as mentioned in Holmgren et al. [The second component of the intervention was the standardised process, where contact with the employer was established and a plan for RTW was elaborated between the patient, the employer, the RC and the GP. It is plausible that this component also prolonged, rather than reduced the time to RTW. The employer´s readiness for RTW may not be in line with the patient´s readiness, and this could potentially prolong the process. Seing et al. [Since we only use sick leave days as an outcome, we have no insight into the patients’ wellbeing after the intervention. It is possible that even though the intervention failed to reduce time to RTW, the elaborated plan for RTW, which was agreed upon with the employer, provided a safe environment that helped reduce symptoms in the intervention group. Glise et al. found [Van Hess et al. [The intervention in this study was based on the PEO model, which emphasizes the importance of considering not only individual factors that affect RTW, but also the work environment and occupation. Previous research has shown that work-related stress is associated to the psychosocial work environment, such as low co-worker support, low supervisor support, low procedural justice, low relational justice and a high effort–reward imbalance [An interesting finding was that the difference between the groups was no longer significant after 24 months. This raises the question whether the results would be different if there was a longer follow-up period, i.e., if the intervention would have promoted more sustainable RTW. A follow-up period of two years can be considered to be quite extensive in comparison to similar studies but still too short to detect differences in relapse into sickness absence between cases and controls. A strength of the present study is that the data on sick leave was retrieved from official registers and not self-reported, reducing the risks for recall bias and drop-out.