Discussion
illnesses like cancer, illness
RECRUITMENT
Our study found weak or no support of any MI effect compared to usual case management or an active control group in terms of future work participation. Although the MI and usual case management group did slightly better than the active control group over time, the groups were closely matched during the first months, making it unlikely that these small differences were due to the intervention. However, only about half of the participants showed up for the MI intervention.Our findings differ from previous studies that have found results indicating a positive effect of MI on RTW, albeit the effects have been small with low precision (The MI intervention included only one stakeholder, the social security office. Due to the complex nature of sick leave, it has been suggested that involvement, coordination, and communication between the different stakeholders are important (Our trial has several strengths: the use of registry data resulted in almost no missing data on the main outcome, the use of an active control group helped to eliminate potential attention bias, the intervention was designed to achieve a biopsychosocial approach to sick leave, and recruitment through NAV ensured no referral bias. The main limitation of our trial was that many participants did not show up for the sessions at the NAV office. This could be due to the inclusion of participants with different diagnoses, including severe illnesses like cancer, but could also be due to the delay between randomization and the intervention, which resulted in many returning to work before the intervention took place. This is also a likely explanation for why participants not showing up for the MI sessions had fewer sickness absence days than those receiving the two sessions. Contamination between the arms is a risk since MI is a tool NAV wants its caseworkers to use. However, the fact that MI may be hard to master might have reduced the risk. In this study, we used the absence of medical benefits as an indicator of being at work. In Norway, employees who are absent from work due to illness are protected from dismissal for the first 12 months. This, combined with a high employment rate for both men and women and a generous insurance system, makes the absence of medical benefits a fair proxy for having returned to work. However, it is important to acknowledge that some individuals may have transitioned to other welfare benefits or received support through by private means. It should also be noted that the last part of the trial took place during the COVID-19 pandemic, this affected the intervention for about 15–20 participants in each group who received the interventions digitally. Furthermore, a large part of the participants, although having completed the intervention, were still enrolled in the trial during the pandemic. It is not possible to know how that affected their sick leave, but there is no reason to believe it affected the groups differently.