A model to evaluate the cost-effectiveness of oral therapies in the management of patients with major depressive disorders.

The introduction of a new antidepressant, venlafaxine, a serotonin norepinephrine reuptake inhibitor (SNRI), has provided researchers with the opportunity to take a closer look at the issues involved in selecting a product for a formulary. To aid decision makers in considering the adoption of this new therapy, a pharmacoeconomic simulation model was developed to evaluate the cost-effectiveness of SNRIs versus traditional oral therapies in the management of patients with major depressive disorders (MDDs) from a cost-based payer perspective. Four treatment regimens for MDD were compared: tricyclic antidepressants, selective serotonin reuptake inhibitors, heterocyclic antidepressants, and SNRIs. The principles of decision analysis were used to calculate outcome probabilities based on data from a meta-analysis. The expected cost of each regimen was calculated using cost data from a survey of three health maintenance organizations located in Missouri, Massachusetts, and California. The model suggests that SNRI therapy demonstrates the highest level of cost-effectiveness in an inpatient setting when using both brand and generic acquisition costs of the drugs. When comparing treatment regimens for out-patients, the generic heterocyclic antidepressants demonstrate the highest level of cost-effectiveness: when using band acquisition costs, the SNRIs demonstrate the highest level of cost-effectiveness. Sensitivity analysis calculated the robustness of the conclusions to all major parameters.