The cost-effectiveness of cognitive behavioral therapy for bulimia nervosa in the Australian context

Objective: This study was to model the cost-effectiveness of specialist-delivered cognitive behavioral therapy for bulimia nervosa (CBT-BN) compared to no intervention within the Australian context. Method: An illness-death model was developed to estimate the cost per disability-adjusted life-year (DALY) averted of CBT-BN over 2 years from the healthcare perspective. Target population was adults aged 18–65 years with BN. Results are reported as incremental cost-effectiveness ratios (ICER) in 2013 Australian dollars per DALY averted. Uncertainty and sensitivity analyses were conducted to test the robustness of results. Results: Primary analysis indicated that CBT-BN was associated with greater DALY averted (0.10 DALY per person) and higher costs ($1,435 per person) than no intervention, resulting the mean ICER of $14,451 per DALY averted (95% uncertainty interval [UI]: $8,762 to $35,650). Uncertainty analysis indicated CBT-BN is 99% likely to be cost-effective at a threshold of $50,000 per DALY averted. Including the patients' time and travel costs resulted in the mean ICER of $18,858 per DALY averted (95% UI: $11,235 to $46,026). Sensitivity analysis indicated the intervention was not cost-effective if over 80% people discontinued treatment. Other analyses including a reduced time horizon, increased remission rates, and 4-month effect size of CBT-BN increases the ICERs but these ICERs remained well below under a threshold of $50,000 per DALY averted. Conclusion: This study has demonstrated that CBT-BN for adults with BN is a cost-effective treatment intervention. Further research is required to investigate the practicability of CBT-ED and the cost-effectiveness of other formats of CBT-BN delivery.