Cost-effectiveness of mirtazapine relative to fluoxetine in the treatment of moderate and severe depression in France

The objective of this study was to estimate the cost-effectiveness of mirta zapine, compared to fluoxetine, in the management of moderate and severe de pression among outpatients in France, from the perspective of the Social Se curity Fund. The economic analysis was based on clinical differences obtained from a six week comparative trial with mirtazapine and fluoxetine, which were extrapo lated to six months using assumptions derived from the literature. Using tr eatment paths developed from the clinical trial data, the published literat ure and interviews with a French Delphi Panel, clinical decision analysis t echniques enabled the expected direct Social Security costs and the expecte d indirect costs due to lost productivity to be estimated over six months a t 1995/96 prices. This study was critically appraised by an Expert Panel wh o endorsed and supported the analysis and its assumptions. Using mirtazapine instead of fluoxetine for six months increased the propor tion of successfully treated patients by 22% (from 15.6% to 19.1%), albeit for a negligible additional Social Security cost of FF117 per patient (from FF22,682 to FF22,799). Consequently, the expected direct cost per patient successfully treated with mirtazapine was FF98,883 compared to FF99,310 for a fluoxetine-treated patient. The expected indirect cost to French society was FF98,883 per mirtazapine-treated patient, compared to FF99,310 per flu oxetine-treated patient. Social Security payments to patients during their time off work emerged as the main cost driver, accounting for up to 86% of the expected direct cost per patient. In contrast, the acquisition costs of antidepressants accounted for between 1% and 3% of the expected direct cos t per patient. The analysis used an acquisition cost (public price) of FF8.98 per 30mg of mirtazapine, but across a range of acquisition costs, up to FF15 per 30mg, mirtazapine remained cost-effective relative to fluoxetine. In conclusion, this study demonstrated that despite the differences in acqu isition costs, mirtazapine is potentially a cost-effective antidepressant c ompared to fluoxetine in the management of moderate and severe depression i n France.