Psychological workplace interventions to prevent major depression: A model-based economic evaluation

Background: This study aimed to evaluate the cost-effectiveness of stress management interventions delivered as universal face-to-face cognitive behavioural therapy (CBT-SMI) and a targeted online program (eSMI) within the Australian context. Method: A population-based Markov model was developed to estimate the cost per quality-adjusted life year (QALY) gained and return on investment (ROI) ratio of the intervention when compared to no intervention. The model comprised a simple disease model, which simulated how each population cohort moves between three health states (at-risk, depressed and dead) over 11 years. The target population consisted of employees in large-sized businesses with permanent or fixed-term contracts. This study considered intervention costs and cost savings associated with health services and productivity impacts (under the partial societal perspective). Probabilistic and one-way sensitivity analyses were conducted to test model assumptions. Results: Findings showed that CBT-SMI was more effective and more costly with an incremental cost-effectiveness ratio of $57,291 per QALY gained and a ROI ratio of 0.28 when compared to no intervention. The eSMI was cost saving and produced a ROI ratio of 1.05. The study findings were robust to changes made in the one-way and probabilistic sensitivity analyses. Conclusion: eSMI was found to be cost saving with a positive ROI ratio. Universal prevention programs are typically resource-intensive and information on how to increase the efficiency of these programs is needed. The program evaluation should be open to a broad scope of outcomes and not simply avoidance of depression cases (such as employees’ wellbeing).