To examine the costs and cost-effectiveness of mirtazapine compared to placebo over 12-week follow-up.

Economic evaluation in a double-blind randomized controlled trial of mirtazapine vs. placebo.

Community settings and care homes in 26 UK centers.

People with probable or possible Alzheimer’s disease and agitation.

Primary outcome included incremental cost of participants’ health and social care per 6-point difference in CMAI score at 12 weeks. Secondary cost-utility analyses examined participants’ and unpaid carers’ gain in quality-adjusted life years (derived from EQ-5D-5L, DEMQOL-Proxy-U, and DEMQOL-U) from the health and social care and societal perspectives.

One hundred and two participants were allocated to each group; 81 mirtazapine and 90 placebo participants completed a 12-week assessment (87 and 95, respectively, completed a 6-week assessment). Mirtazapine and placebo groups did not differ on mean CMAI scores or health and social care costs over the study period, before or after adjustment for center and living arrangement (independent living/care home). On the primary outcome, neither mirtazapine nor placebo could be considered a cost-effective strategy with a high level of confidence. Groups did not differ in terms of participant self- or proxy-rated or carer self-rated quality of life scores, health and social care or societal costs, before or after adjustment.

On cost-effectiveness grounds, the use of mirtazapine cannot be recommended for agitated behaviors in people living with dementia. Effective and cost-effective medications for agitation in dementia remain to be identified in cases where non-pharmacological strategies for managing agitation have been unsuccessful.

Depression is a common and costly comorbidity in dementia. There are very few data on the cost-effectiveness of antidepressants for depression in dementia and their effects on carer outcomes.

To evaluate the cost-effectiveness of sertraline and mirtazapine compared with placebo for depression in dementia.

A pragmatic, multicentre, randomised placebo-controlled trial with a parallel cost-effectiveness analysis (trial registration: ISRCTN88882979 and EudraCT 2006-000105-38). The primary cost-effectiveness analysis compared differences in treatment costs for patients receiving sertraline, mirtazapine or placebo with differences in effectiveness measured by the primary outcome, total Cornell Scale for Depression in Dementia (CSDD) score, over two time periods: 0–13 weeks and 0–39 weeks. The secondary evaluation was a cost-utility analysis using quality-adjusted life years (QALYs) computed from the Euro-Qual (EQ-5D) and societal weights over those same periods.

There were 339 participants randomised and 326 with costs data (111 placebo, 107 sertraline, 108 mirtazapine). For the primary outcome, decrease in depression, mirtazapine and sertraline were not cost-effective compared with placebo. However, examining secondary outcomes, the time spent by unpaid carers caring for participants in the mirtazapine group was almost half that for patients receiving placebo (6.74 v. 12.27 hours per week) or sertraline (6.74 v. 12.32 hours per week). Informal care costs over 39 weeks were £1510 and £1522 less for the mirtazapine group compared with placebo and sertraline respectively.

In terms of reducing depression, mirtazapine and sertraline were not cost-effective for treating depression in dementia. However, mirtazapine does appear likely to have been cost-effective if costing includes the impact on unpaid carers and with quality of life included in the outcome. Unpaid (family) carer costs were lower with mirtazapine than sertraline or placebo. This may have been mediated via the putative ability of mirtazapine to ameliorate sleep disturbances and anxiety. Given the priority and the potential value of supporting family carers of people with dementia, further research is warranted to investigate the potential of mirtazapine to help with behavioural and psychological symptoms in dementia and in supporting carers.