Health economic evaluation of the danish ibbis randomised controlled trials

Common mental disorders (CMDs), including depression, anxiety, and stress-related disorders, affect approximately 20% of the adult population, significantly impacting labor market participation and productivity. The IBBIS Trials aimed to evaluate the health economic impact of integrating healthcare and vocational rehabilitation for sick-leave benefit recipients with CMDs. Two parallel randomised controlled trials (RCTs) were conducted involving adults on sick leave for at least four weeks, diagnosed with either anxiety or depression, or stress-related disorders. Participants were randomised into three groups: Service As Usual (SAU), IBBIS Mental Health Care (MHC), and IBBIS Integrated Intervention (INT). Data were collected from Danish national registers, including health services, vocational rehabilitation, and social benefit transfers. Economic outcomes were analysed from both societal and government budget perspectives over a 24-month follow-up period. Both IBBIS interventions (INT and MHC) resulted in negative economic impacts compared to SAU. At 24 months, INT showed a net societal cost of €4,645 per participant and MHC a net cost of €7,680. From a government budget perspective, the corresponding net costs were €2,994 for INT and €5,831 for MHC. The primary driver was reduced productivity, with no significant counterbalancing improvements in health-related quality of life. The interventions did not achieve cost-effectiveness, emphasising the need for new treatments that effectively reduce sickness absence and enhance workability post-return-to-work. The trials have shown that current interventions are under pressure and fall short of providing the expected economic and health benefits, making it essential to develop innovative strategies that truly support individuals’ return to work. The IBBIS Trials highlight the economic challenges of current CMD interventions and underscore the importance of addressing both health and vocational outcomes to achieve meaningful economic benefits. Developing and testing new approaches that can provide real value and support to those affected by CMDs is still an important unresolved research area. Pre-registered on www.osf.io (doi: https://doi.org/10.17605/osf.io/d8pq2 ).