Cost-Effectiveness of Group Transdiagnostic Cognitive Behavioural Therapy for Anxiety Disorders in Primary Care...

To assess the incremental cost-effectiveness ratio (ICER) of group transdiagnostic cognitive-behavioural therapy (tCBT) added to treatment as usual (TAU) for anxiety disorders compared to TAU only from the healthcare system perspective over a 1-year time horizon.

Data from a pragmatic multisite randomized controlled trial where adults (18-65 years) with an anxiety disorder were randomized to tCBT + TAU (n = 117) or TAU (n = 114). Group tCBT is a 12-week (2h weekly sessions) community-based intervention. Health service utilization and related costs were captured from medico-administrative data and included those for the intervention, ambulatory visits, hospitalizations and medications. Effectiveness was based on quality-adjusted life years (QALYs). The study included measures at baseline, 4, 8, and 12 months. Intention-to-treat and complete case analyses were carried out. Missing data were imputed using multiple imputation analyses. Seemingly unrelated regression analyses were used to assess the effect of the intervention on total costs and QALYs while also adjusting for baseline confounders. The probability of cost-effectiveness of the intervention was assessed according to different willingness-to-pay (WTP) thresholds using the net benefit regression method.

The ICER of tCBT + TAU as compared to TAU in the intention-to-treat analysis was $6,581/QALY. Complete case analyses showed a similar ICER of $6,642/QALY. The probability at a WTP threshold of $20,000 and $40,000 that tCBT + TAU as compared to TAU is cost-effective is 93.0% and 99.9%.

tCBT added to TAU appears to be cost-effective from the healthcare system perspective for treating adult patients with anxiety disorders. Larger trials including young and older adults as well as a range of anxiety disorders are needed to further investigate the cost-effectiveness of tCBT in different patient populations.