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

This study estimated the cost-effectiveness of mirtazapine, compared it, am itriptyline, in the management of moderate and severe depression among outp atients in France. from the perspective of the Social Security Fund. The economic analysis was based on significant clinical differences obtaine d from a meta-analysis of four randomised trials comparing mirtazapine with amitriptyline in th: US. A decision model of the treatment paths and assoc iated resource use attributable tl, managing moderate and severe depression in France was developed from the trial data, information on French clinica l practice obtained from interviews with a French Delphi panel and publishe d literature. Decision analysis techniques enabled the expected direct Soci al Security costs and the expected indirect societal costs due to lost prod uctivity to be estimated over 28 weeks at 1995/96 prices. This study was cr itically appraised by an Expert Panel who endorsed and supported the analys is and its assumptions. Using mirtazapine instead of amitriptyline for 28 weeks increased the propo rtion of successfully treated patients by 21% (from 19.2% to 23.2%) and red uced the expected Social Security cost from FP-22,310 to FF23,096. Conseque ntly, the expected direct cost per patient successfully treated with mirtaz apine was FF96,263 compared to FF120,475 for an amitriptyline-treated patie nt. Patients treated with mirtazapine and amitriptyline for 28 weeks were e xpected to miss 17.49 and 18.37 weeks of work respectively, due to their de pression. Hence, the expected indirect cost to French Society over this per iod was estimated to be FF96,507 and FF101,321 per patient respectively. Th e expected cost-differences were largely accounted for by the difference in the cost of managing adverse events and the Social Security payments made to patients during their time off work. Social Security payments were the m ain cost driver, accounting for up to 86% of the expected direct cost per p atient. In contrast, the acquisition costs of antidepressants accounted for between 1% and 3% of the expected direct cost per patient. The analysis used an acquisition cost (public price) of FF8.98 per 30mg of mirtazapine. Sensitivity analyses showed that across a range of acquisition costs for mirtazapine, up to FF15 per 30mg. mirtazapine remained cost-effe ctive relative to amitriptyline. In conclusion, this study demonstrated that despite the differences in acqu isition costs, mirtazapine is a cost-effective antidepressant compared to a mitriptyline in the management of moderate and severe depression in France.