Developing thai economic model to study cost-effectiveness of switching to bupropion compared to combination with bupropion after the failure of an SSRI for major depressive disorder.
OBJECTIVE
To present an economic model and cost-effectiveness estimates of switching to bupropion compared to combination with bupropion after failure of an SSRI for major depressive disorder (MDD).


MATERIAL AND METHOD
An economic model was developed to simulate the transitions of Thai outpatients with nonpsychotic MDD who had no remission or could not tolerate the SSRI citalopram and received either sustained-release bupropion monotherapy as switching strategy or sustained-release bupropion plus citalopram as combination strategy. Clinical data were obtained form 2 trials of the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study. The four event probabilities: remission rates, rates of non-remission, discontinuation rates due to intolerance, and incidence of serious adverse events were estimated. Direct costs included drug cost, hospitalizations, and electroconvulsive therapy (ECT). The primary outcome considered in the model was a remission of symptoms. Outputs were measured in terms of costs per remission and costs per quality-adjusted life-years (QALYs).


RESULTS
In the base-case analysis, the total direct costs with a bupropion switch were 22,937 THB per remission and 29,346 THB per remission with a bupropion combination. Compared with combination option, switching to bupropion also had lower total cost per QALY (28,672 THB vs. 36,682 THB) and had cost saving of 21.8%. The incremental cost-effectiveness of the combination regimen compared with the switching regimen was 6,409 THB per remission gained and 8,011 THB per QALY gained. In a sensitivity analysis, combination strategy dominated switching strategy if the value of the transitional probability of remission changed to a value of greater than 0.547.


CONCLUSION
The economic model indicated that treatment of MDD patients who fail to achieve remission from an SSRI with a switch to bupropion is a cost-effectiveness treatment option compared with a combination of SSRI with bupropion.