Cost-utility analysis of adjunctive psychosocial therapies in bipolar disorder

There are few economic evaluations of adjunctive psychosocial therapies for bipolar disorder.

Estimate the cost-utility of in-person psychosocial therapies for adults with bipolar disorder added to treatment as usual (TAU), from an Australian Government perspective.

We developed an economic model, estimating costs in 2021 Australian dollars (A$) and outcomes using quality-adjusted life-years (QALYs) gained and disability-adjusted life-years (DALYs) averted. The model compared psychoeducation, brief psychoeducation, carer psychoeducation, cognitive-behavioural therapy (CBT) and family therapy when added to TAU (i.e. pharmacotherapy) over a year for adults (18-65 years) with bipolar disorder. The relative risk of relapse was sourced from two network meta-analyses and applied to the depressive phase in the base case. Probabilistic sensitivity analysis and one-way sensitivity analyses were conducted, assessing robustness of results.

Carer psychoeducation was preferred in the base case when the willingness-to-pay (WTP) threshold is below A$1000 per QALY gained and A$1500 per DALY averted. Brief psychoeducation was preferred when WTP is between A$1000 and A$300 000 per QALY gained and A$1500 and A$450 000 per DALY averted. Family therapy was only preferred at WTP thresholds above A$300 000 per QALY gained or A$450 000 per DALY averted. In sensitivity analyses, brief psychoeducation was the preferred therapy. Psychoeducation and CBT were dominated (more costly and less effective) in base-case and sensitivity analyses.

Carer and brief psychoeducation were found to be the most cost-effective psychosocial therapies, supporting use as adjunctive treatments for adults with bipolar disorder and their families in Australia.