Evaluating the health and economic impacts of return-to-work interventions: a modelling study.

Objectives: The rate of sickness absence in Norway is at its highest point since 2009 and policy makers need tools to make informed decisions on high-value interventions to address sick leave. Using trial-linked registry data, multi-state modelling, and decision-analytic modelling, we assessed the cost-effectiveness of two return-to-work (RTW) interventions for individuals with musculoskeletal and psychological disorders in Norway.

Methods: Using data from 166 individuals in a randomized trial, we developed a decision-analytic model to compare two multi-domain RTW interventions: O-ACT (outpatient acceptance and commitment therapy) and I-MORE (inpatient multimodal occupational rehabilitation). The probabilistic model was informed using trial-based input parameters, including transition probabilities, healthcare costs, production loss, and health-related quality of life to project long-term costs and quality-adjusted life years (QALY) over a 25-year time horizon for each intervention.

Results: Modelled outcomes were consistent with the trial outcomes, showing that I-MORE led participants to RTW more quickly. However, assuming a healthcare perspective and a cost-effectiveness threshold of $50,000 per QALY, I-MORE was not considered cost-effective in 98% of our simulations (probabilistic ICER: $356,447 per QALY gained) compared to O-ACT. In contrast, when accounting for production loss, I-MORE not only became cost-effective but was projected to be more beneficial and less costly compared to O-ACT.

Conclusion: Under current Norwegian benchmarks for cost-effectiveness, I-MORE would not be considered cost-effective unless production loss was included. Our findings emphasize the key role of a broader societal perspective in economic evaluations, which although is being considered, is currently not recommended in Norwegian guidelines.