Early intervention for subthreshold panic disorder in the Netherlands: A model-based economic evaluation from a societal perspective

BACKGROUND: Panic disorder (PD) is associated with impaired functioning and reduced quality of life. In the Netherlands, almost 2% of the population experiences clinically relevant panic symptoms without meeting the diagnostic criteria for PD, which is referred to as subthreshold PD (STHPD). Evidence suggests that subthreshold mental disorders may have a similar impact on quality of life and functioning in comparison with full-blown mental disorders, which draws attention to the need for interventions for STHPD. These interventions are currently not systematically provided in clinical practice. This study aims to investigate the population cost-effectiveness of adding a CBT-based early intervention for adults with STHPD to the existing health care for people with PD in the Netherlands. METHODS: A health-economic Markov model was constructed in order to compare quality adjusted life-years (QALYs) and societal costs of adding an early intervention to usual care for PD. The model compares usual care with an alternative program in which usual care is supplemented with a CBT-based early intervention. Input parameters for the model were derived from national sources and published literature where possible, and based on expert opinion otherwise. Probabilistic and deterministic sensitivity analyses were conducted to evaluate the uncertainty of the model input parameters. RESULTS: On average, the added CBT-based early intervention was dominant in comparison with usual care, meaning that the early intervention yielded more QALYs at lower costs. At a willingness-to-pay threshold of €20,000 per QALY, the cost-effectiveness probability of the added early intervention was 98%. Sensitivity analyses showed that the results were robust. CONCLUSIONS: This study showed that offering an early intervention in addition to usual care for PD is potentially cost-effective, but it should be further investigated to what extent trial results can be extrapolated to the level of the population before such interventions are implemented on a large scale.