This study estimated the cost-effectiveness of mirtazapine, compared to amitriptyline and fluoxetine, in the management of moderate and severe depression in Austria, as well as the costs related to the discontinuation of antidepressant treatment from the perspective of the Austrian Sick Funds (Gebietskrankenkassen).
The economic analyses were based on a meta-analysis of four randomised clinical trials comparing mirtazapine with amitriptyline, and on a six week comparative trial of mirtazapine and fluoxetine which was extrapolated to six months using assumptions derived from the literature. Decision models of the treatment paths and associated resource use attributable to managing moderate and severe depression in Austria were developed from clinical trial data, information on Austrian clinical practice obtained from interviews with an Austrian Delphi panel (comprising psychiatrists and GPs), and from published literature. The models were used to estimate the expected costs to the Gebietskrankenkassen of managing a patient with moderate or severe depression, and the indirect cost per patient to Austrian society due to lost productivity.
The expected cost to the Gebietskrankenkassen of healthcare resource use attributable to managing a patient suffering from moderate or severe depression who discontinues antidepressant treatment was estimated to be ATS 4,088 over five months, of which hospitalisations accounted for nearly 69% of the cost.
Using mirtazapine instead of amitriptyline for 28 weeks increases the proportion of successfully treated patients by 21% (from 19.2 to 23.2%), and reduces the expected cost to the Gebietskrankenkassen by ATS 1,112 per patient (from ATS 31,411 to ATS 30,299). Patients treated with mirtazapine and amitriptyline for 28 weeks are expected to miss 4.76 and 5.01 weeks of work respectively, due to their depression. Hence, the expected indirect cost to Austrian society over this period was estimated to be ATS 58,787 and ATS 61,851 per patient respectively.
Using mirtazapine instead of fluoxetine for six months increases the proportion of successfully treated patients by 22% (from 15.6 to 19.1%), albeit for a negligible additional cost to the Gebietskrankenkassen of ATS 408 per patient (from ATS 29,205 to ATS 29,613). Patients treated with mirtazapine and fluoxetine for six months are expected to miss 4.53 weeks of work, due to their depression. Hence, the expected indirect cost to Austrian society due to lost productivity was estimated to be ATS 55,900 per patient with either antidepressant.
In conclusion, this study suggests that despite the differences in acquisition costs, mirtazapine is a cost-effective antidepressant compared to amitriptyline and fluoxetine, supporting the adoption of this treatment in the management of moderate and severe depression in Austria.